Practical Manual for the Use of Soils and Rocky Materials in Embankment Construction

ISSN 1151-1516

techniques et méthodes des laboratoires des ponts et chaussées

Guide technique

Practical manual for the use of soils and rocky materials in embankment construction

EXCERPTS from Guide technique “Réalisation des remblais et des couches de formes” [acronym “GTR”] (Technical Guideline on “Embankment and Capping Layer Construction”)

Practical manual for the Use of soils and rocky materials in embankment construction

September 2003

Laboratoire Central des Ponts et Chaussées 58, boulevard Lefebvre - 75732 PARIS Cedex 15 - France

This document has been produced under the joint responsability of the LCPC and SETRA research organizations The GTR was drawn up by the following work group: MM

J.-F. S.H. A. D. J. H. J.-P. G. A. B. J.-P. D. M. B.

CORTÉ EDME FÈVRE GILOPPE GIROUY HAVARD JOUBERT MOREL PERROT de PILLOT PUECH PUIATTI SCHAEFFNER URCEL

LCPC (Division Géotechnique mécanique des chaussées) Entreprise Müller Frères CETE Normandie-Centre (LRPC de Rouen) CETE Normandie-Centre (DESGI) Direction des Infrastructures du Département de la Charente-Maritime CETE de l’Ouest (LRPC d’Angers) SETRA CER de Rouen CETE de l’Est (LRPC de Nancy) CETE de Lyon (DES) Scétauroute Société des Chaux et Dolomies du Boulonnais S.A. LCPC (Division Géotechnique mécanique des chaussées) DDE des Hauts-de-Seine

CORTÉ FÈVRE HAVARD JOUBERT KERGOET MOREL PERROT QUIBEL SCHAEFFNER VEYSSET

LCPC (Division Géotechnique mécanique des chaussées) CETE Normandie-Centre (LRPC de Rouen) CETE de l’Ouest (LRPC d’Angers) SETRA LRPC de l’Est parisien CER de Rouen CETE de l’Est (LRPC de Nancy) CER de Rouen LCPC (Division Géotechnique mécanique des chaussées) CETE de Lyon (LRPC de Lyon)

and written by: MM

J.-F. A. H. J.-P. M. G. A. A. M. J.

Under responsibility of Scientific and Technical Network of the french Ministery of Equipement This Practical Manual was prepared by: MM

J.-F. H.

CORTÉ HAVARD

LCPC (Direction technique “Chaussées”) LCPC (Direction technique “Géotechnique”)

And translated by: NORTRAD and the translation kindly reviewed by: Mme

J. DEZART

Entreprise Guintoli (France)

The distribution of this document is supported by:

To order this publication: Laboratoire Central des Ponts et Chaussées - IST - Diffusion des Editions - 58, boulevard Levebvre F - 75732 - Paris Cedex 15 - Phone: 01 40 43 50 20 - Fax: 01 40 43 54 95 - Internet: http://www.lcpc.fr Price: 23 Euros HT This document is property of the LCPC organization and may not be copied or reproduced in any form, even partially, without the express authorization of the LCPC Managing Director (or one of the Director’s authorized representatives). © 2003 - LCPC ISSN 1151-1516 ISBN 2-7208-3116-4

Table of contents Notice

5

1. Field of application 2. References

7 7

2.1 2.2

7 8

Bibliography and Technical References Relevant Standards

3. Abbreviations and symbols

9

4. Classification of rocks and soils 4.1 4.2 4.2.1 4.2.2 4.2.3 4.3 4.3.1 4.3.2

Rock and Materials Displaying Special Behaviour Soils Grain size characteristics Clay characteristics State characteristics Summary of classification Summary table of the classification of rock and soil types Classification according to type and state

5. Use of rocks and soils in embankment construction 5.1 5.2

Rock and Materials Displaying Special Behaviour Soils

6. Compaction of fill 6.1 6.2 6.2.1 6.2.2 6.2.3 6.2.4 6.2.5 6.3 6.3.1 6.3.2 6.4 6.4.1 6.4.2

10 14 14 14 15 17 17 18

26 27 29

36

Definition of specifications Classification of compaction plant Pneumatic tyred rollers (Pi) Smooth vibrating drum rollers (Vi) Vibrating rollers (VPi) Static tamping rollers (SPi) Vibrating plate compactors (PQi) Compaction specifications Use of Tables - Examples of Application Compaction tables Continuous monitoring of compaction Specifications Monitoring Operations

36 37 37 37 40 40 40 41 41 43 54 54 55

7. Particular case of use of arid soils 7.1 7.2 7.2.1 7.2.2 7.2.3 7.2.4 7.3 7.4 7.5 7.6

10

Advantages of, and basis for dry compaction Definition of arid soils - Application scope of the method Nature of concerned soils Definition of moisture state “arid” “Arid” state classes of soils Acceptable embankment height Compaction tables Particularities of dry compaction “Dry compaction” trial embankments Special site organisation for “Dry compaction” 3

57 57 57 57 57 58 58 58 58 59 59

Notice his Manual is an excerpt from the Technical Guidelines on Embankment and Capping Layers Construction (abbreviated to its French acronym GTR) issued September 1992 in France by LCPC 1 and SETRA 2. The Guidelines are the basic standard engineering reference work in France on the construction of embankments and capping layers. This excerpt from the Guidelines concerns only the part dealing with the classification of natural soils and their use in embankments (excluding all reference to organic topsoils and industrial products) and requirements for their use in capping layers construction). This Manual is a broader development of a more specific project undertaken in 1998 at the request of the Executive Council for Major Works in Lebanon with a view to compiling a Lebanese standard on the construction of fill structures under the aegis of LIBNOR. The GTR rock classification system (see section 4-1 below) addresses only those rocks commonly found in France. Experience has shown that the use of the Manual in another country may justify reducing or extending the classification system to adapt its content to the rocks encountered with respect to earthmoving work not included in GTR, if such changes were considered relevant.These changes do not appear to be required in the soil classification system (see section 4-2). Earthworks in specific meteorological area (for instance very hot or very cold ones) need adaptations to take into account difficulties produced by natural moisture content.

T

Caveat Language - This practice offers a set of instructions for performing one or more specific operations. This document cannot replace education and experience and should be used in conjunction with professional judgment. Not all aspects of this practice may applicable in all circumstances. This manual is not intended to represent or replace the standard of care by which the adequacy of a given professional service must be judged, nor should this document be applied without consideration of a project’s many unique aspects.

1. Laboratoire Central des Ponts et Chaussées, 58 boulevard Lefebvre, 75732 Paris Cedex 15, France, tel. (33) 1 40 43 50 00, fax (33) 1 40 43 54 98 2. Service d'Etudes des Routes et Autoroutes, Centre de Sécurité et des Techniques Routières, 46 avenue Aristide Briand, BP 100, 92223 Bagneux Cedex, France, tel. (33) 1 46 11 31 31, fax (33) 1 46 11 31 69

5

Use of soils and rocky materials in embankment construction • Field of application

1. Field of application This Manual - classifies naturally-occurring soils on the basis of laboratory classification tests (chiefly with respect to their potential use as a fill material), - specifies the soil categories suitable for incorporation in embankments and the relevant conditions of use, - describes the main methods construction and any restrictions specific to categories. The section dealing with compaction of fill puts forward a suggested classification of compaction machinery offering a standard of construction compatible with the quality goals commonly associated with such work, and a method for continuously monitoring actual compaction performance. A special method of compaction of “arid” soils often found in arid countries is also proposed in chapter 7. The particular precautions mentioned in this chapter are then required. This method is not a substitute for proper design, which must address project-specific factors such as available soil types and condition, balanced cut and fill, conditions in the underlying ground, embankment structure when the constituent soils are not uniform, embankment face slopes, drainage, local climate and weather conditions over the construction period, erosion risk, etc. In addition to the rules of the present document, it is necessary to carry out a specific stability study for embankments the height of which exceed 15 to 20 metres.

2. References 2.1 Bibliography and Technical References This Manual is an excerpt from the Technical Guidelines on Embankment and Capping Layer Construction (abbreviated to its French acronym GTR) issued September 1992 in France by LCPC3 and SETRA4. The Guidelines are substantially the only standard engineering reference work in France for the construction of embankments and capping layers. This Manual concerns only the part of the Guidelines dealing with the classification of natural soils and their use in embankments. Reference should be made to the Guidelines for detailed explanation and in some cases engineering justification for the arrangements recommended herein, because the Manual takes only the practical recommendations from the Guidelines, to avoid overburdening the work. It is however important to note that the Manual differs from the Guidelines in the following respects: - Organic topsoils and industrial products in the GTR classification have been ignored because their use is too dependent on environmental legislation and cannot be readily transposed from one country to another. - Soil class D3 has been deleted from the classification (being not necessary). - Criteria for use which involves specific plant (full-depth excavation or bench excavation) or modification of the soil moisture state (particularly wetting over-dry material) have not been kept because they are likely to be difficult to meet in the field. Nevertheless, if site conditions are such as to allow the soil moisture to be improved or even completely changed, this fact is addressed in the Manual in the site condition classification. 3. Laboratoire Central des Ponts et Chaussées, 58 Boulevard Lefebvre, 75732 Paris Cedex 15, France, tel. (33) 1 40 43 50 00, fax (33) 1 40 43 54 98 4. Service d'Etudes des Routes et Autoroutes, Centre de Sécurité et des Techniques Routières, 46 Avenue Aristide Briand, BP 100, 92223 Bagneux Cedex, France, tel. (33) 1 46 11 31 31, fax (33) 1 46 11 31 69

7

Use of soils and rocky materials in embankment construction • References

The engineering justification of the content of this document has been established experimentally by the systematic use, from 1976 to 1992, of very similar rules to those in the GTR, laid down at the time by Recommendations on Road Earthworks (abbreviated RTR, a document given official status in France at the time by the standard public contract specifications for highways), which very broadly speaking, led to stable fill structures being built. Experience acquired and records of construction conditions and performance of the structures built in this way led to improvements to the RTR on several points when preparing the Technical Guidelines on Embankment and Capping Layer Construction (GTR). Apart from the experimental justification offered by successful projects, extensive trials had been conducted under controlled conditions, especially for drafting the compaction specifications. The justifications of the particular method proposed for re-use of arid soils can be found in the chapter 7.

2.2 Relevant Standards The Manual makes reference to the following French standards issued by AFNOR (Association Française de Normalisation, Tour Europe, 92049 Paris La Défense Cedex, France): XP P 18-540 - Aggregate - Definitions, Compliance, Specifications (Oct. 1997) 5 XP P 18-572 - Micro-Deval Abrasion Test (Dec. 1990) 5 XP P 18-573 - Los Angeles Test (Dec. 1990) XP P 18-574 - Dynamic Fragmentation Test (Dec. 1990) XP P 18-576 - Determination of Sand Friability Coefficient (Dec. 1990) XP P 18-593 - Sensitivity to Frost (Dec. 1990) 5 XP P 18-598 - Sand Equivalent (Oct. 1991) NF P 11-300 - Earthwork Construction - Classification of materials for use in the construction of highway embankments and capping layers (Sept. 1992) NF P 11-301 - Earthwork Construction - Terminology (Dec. 1994) NF P 94-040 - Soils: Investigations and Tests - Simplified method of classifying the 0-50mm fraction of granular material - Determination of grain sizes and methyl blue value (Oct. 1993) NF P 94-049-1 - Soils: Investigations and Tests - Determination of moisture content (by weight) of materials - Part 1: Microwave oven drying method (Feb. 1996) NF P 94-049-2 - Soils: Investigations and Tests - Determination of moisture content (by weight) of materials - Part 2: Hotplate and radiator methods (Feb. 1996) NF P 94-050 - Determination of moisture content (by weight) of materials - Autoclave method (Sept. 1995) NF P 94-051 - Soils: Investigations and Tests - Determination of Atterberg Limits - Liquid limit (cup method) - Plastic limit (roll method) - March 1993 NF P 94-052-1 - Soils: Investigations and Tests - Determination of Atterberg Limits - Part 1 - Liquid limit (cone penetration method) (Nov. 1995) NF P 94-054 - Soils: Investigations and Tests - Determination of unit weight of solid particles - Water pycnometer method (Oct. 1991) NF P 94-056 - Soils: Investigations and Tests - Grain size analysis - Wash, dry and screen method (March 1996) NF P 94-061-1 - Soils: Investigations and Tests - Determination of unit weight of in-place material - Part 1 - Direct transmission probe gammadensimeter method (Oct. 1996) NF P 94-061-2 - Soils: Investigations and Tests - Determination of unit weight of in-place material - Part 2 - Membrane densimeter method (March 1996) NF P 94-061-3 - Soils: Investigations and Tests - Determination of unit weight of in-place material - Part 3 - Sand method (April 1996) 5. This standard remains valid but will be superseded on 1st December 2003 by a European standard already issued, designated NF EN.

8

Use of soils and rocky materials in embankment construction • Abbreviations and symbols

NF P 94-061-4 - Soils: Investigations and Tests - Determination of unit weight of in-place material - Part 4 - Method for coarse materials (Dmax > 50mm) (Dec. 1996) NF P 94-062 - Soils: Investigations and Tests - Determination of in-place unit weight - Twin probe gamma diagraphy (11 pages) (Aug. 1997) XF P 94-063 - Soils: Investigations and Tests - Compaction testing - Constant energy penetrometer method - Principle and method of calibrating penetrodensitographs - Reduction of results - Interpretation (Aug. 1997) NF P 94-064 - Soils: Investigations and Tests - Dry unit weight of rock element - Hydrostatic weighing method (Nov. 1993) NF P 94-066 - Soils: Investigations and Tests - Fragmentation coefficient of rock material (Dec. 1992) NF P 94-067 - Soils: Investigations and Tests - Degradability coefficient of rock material (Dec. 1992) NF P 94-068 - Soils: Investigations and Tests - Determination of methyl blue absorption capacity of soil and rock material by the stain test (Oct. 1998) NF P 94-078 - Soils: Investigations and Tests - Post-immersion CBR - Immediate CBR Immediate bearing index IPI - Determination on sample compacted in CBR mould (May 1997) NF P 94-093 - Soils: Investigations and Tests - Determination of compaction references of material - Proctor normal test - Modified Proctor test (Oct. 1999) NF P 94-100 - Soils: Investigations and Tests - Materials treated with lime and/or hydraulic binders - Soil treatment suitability test (Aug. 1999) NF P 98-705 - Highway construction and maintenance plant and equipment - Compaction plant and equipment - Terminology and trade specifications (1992) NF P 98-713 - Qualification of roadmaking plant and equipment - Methods for testing compaction plant performance NF P 98-736 - Highway construction and maintenance plant and equipment - Classification of compaction plant NF P 98-760 - Highway construction and maintenance plant and equipment - Pneumatic tyred rollers - Evaluation of soil contact pressure (1992) NF P 98-761 - Highway construction and maintenance plant and equipment - Compaction plant - Evaluation of eccentric moment (1992) NF P 98-234.2 - Carriageway tests - Frost performance - Part 2 - Frost swelling test for treated and untreated soils and granular materials with Dmax = 20mm (Feb. 1996)

3. Abbreviations and symbols The following abbreviations and symbols are used in this Manual. LH

Hydraulic binders

Soil state

th h m s ts

very wet wet moderately wet dry very dry

Test results

DG Dmax ES FR FS Ic

Degradability coefficient (%) Maximum soil grain size (mm) Sand equivalent (%) Fragmentation coefficient (%) Sand friability coefficient (%) Consistency index

9

Use of soils and rocky materials in embankment construction • Classification of rocks and soils

Ip IPI LA MDE VBS wn wOPN ρd

Plasticity index (%) Immediate bearing index (%) Los Angeles coefficient (%) measured on 10-14mm fraction (if unavailable, on 6.3-10mm fraction) Micro-Deval coefficient in water (%) measured on 10-14mm fraction (if unavailable, on 6.3-10mm fraction) Methyl blue absorption of soil measured on 0-50mm fraction (grams methyl blue per 100g soil) Natural moisture content (%) Standard Proctor optimum moisture content (%) Bulk unit weight of dry rock sample

4. Classification of rocks and soils 4.1 Rock and materials displaying special behaviour Prior to excavation, a material may often look like rock and one cannot decide just what type of soil it will form after removal. Some more or less loose materials may also display special behaviour on excavation, during placement and/or in the completed works, so that the classification system presented below in section 4-2 cannot adequately describe them (chalk is an example of this). Such materials must nevertheless be characterised at the design stage in order to plan how they can be used in the works and what difficulties their behaviour might present. Usually, engineers simply classify the resulting soil except if the class assigned in this section to the original rock, juxtaposed with the soil classification, adds extra information which can be usefully preserved in view of the special behaviour of the resulting soil (as with chalk). The characterisation of such materials (rock and materials displaying special behaviour) begins by naming the material in geological terms. The materials listing below is based on experience gained in France up to the present time, considered relevant to earthwork construction. It might be expanded as needs arise and more knowledge is amassed.

R1 CHALKS a - Description Material formed by the accumulation of falling calcite particles of the order of 1 to 10 μm in size. This structure is all the more fragile in that the material is very porous (or conversely, its dry density is low). During earthmoving operations, it produces a quantity of fines, directly related to the fragile accumulative structure. When chalk is saturated or near-saturated, the pore water wets these fines so that they behave like a paste, hampering the movement of the construction plant and

Earthworks in chalk.

10


causing pore pressures to build up in the fill. Conversely, dry chalk is a rigid material with good load-bearing performance, but compaction is difficult. Some very wet low density chalks may continue to fragment after they are placed mainly due to applied stresses and frost.

b - Classification Chalks are classified according to their dry density ρd and moisture content wn as shown below ρd > 1.7 1.5 1.5 1.5 1.5

< < < <

ρd ρd ρd ρd

ρd ρd ρd ρd ρd

1.5 1.5 1.5 1.5 1.5

R11

1.7 1.7 1.7 1.7

R2 SUNDRY

and and and and

wn 27 22 wn < 27 18 wn < 22 wn < 18

R12 h R12 m R12 s R12 ts

and and and and and

wn 31 26 wn < 31 21 wn < 26 16 wn < 21 wn < 16

R13 R13 R13 R13 R13

th h m s ts

CALCAREOUS ROCKS

(Coarse-grained limestone, travertine, massive limestone, etc.)

a - Description This class contains the whole range of calcareous rock materials. Their predominant feature in respect of their use in fill is their friability and, for the more fragmentable materials, frost susceptibility. Broadly speaking, the materials are not evolutive rock materials (see argillaceous rock below) and raise no particular problems when used in fill. Because of their friability, attrition and crumbling may produce fines liable to make the material sensitive to water under heavy traffic.

b - Classification The more compact calcareous rocks are classified according to their resistance in the micro-Deval test, while softer rocks are classified according to their bulk unit weight: MDE 45

R21

MDE > 45 and ρd > 1.8

R22

ρd 1.8

R23

Earthworks in limestone.

11


R3 ARGILLACEOUS

ROCKS

(Marls, shales, claystone, pelite, etc.)

a - Description They are characterised by a more or less resistant (usually carbonate) structure with a highly variable proportion (5 % to 95 % from what is generally reported) of potentially swelling clay minerals imprisoned. They fragment to varying degrees when worked, freeing plastic, water-sensitive fines. Breakdown of the structure may continue subsequent to being placed, under the mechanical stresses applied by the overlying fill, and through weathering of large pieces of intact rock due to swelling of the clay minerals in contact with water causing destruction of the rock skeleton. This process and associated distress to the fill is more likely when the materials are less fragmented and display uniform grain size in the completed fill. For the more fragmentable rocks (class R34), their 0-50mm fraction must be characterised.

1

b - Classification The evolutive nature of these rocks is determined by two tests: • Fragmentation test (to French standard NF P 94-066) to assess, from the FR results, the sensitivity of the rock to the fragmentation energy applied on site. • Degradability test (to French standard NF P 94067) to evaluate, from the DG result, the weathering resistance in contact with water by measuring the effects of wetting and drying cycles. For the more fragmentable rocks (class R34 materials), the natural moisture content wn is compared to their normal Proctor optimum wOPN or their immediate bearing index IPI is measured to determine their hydrous state. These rocks therefore classify as follows:

2

3 Rocky marls evolving from a sound, just extracted state (1) to a clay (3) by the halfway of (2).

Fragmentability

Degradability

Class

FR 7

DG > 20 5 < DG 20 DG 5

R31 R32 R33

FR > 7

[wn 1.3 wOPN or IPI < 2*] [1.1 wOPN wn < 1.3 wOPN or 2 IPI > 5*] 0.9 wOPN wn < 1.1 wOPN 0.7 wOPN wn < 0.9 wOPN

R34th R34h R34m R34s

* Values in italics are recommended

12


R4 SILICEOUS

ROCKS

(sandstone, puddingstone, breccia, etc.)

a - Description This class of materials can be likened to assemblies of sand grains (as in sandstone) or stones (breccia and puddingstone) cemented together with silica or calcite. The strength of the binding material affects the behaviour of the rock (in particular there is a risk of rearrangement after placement if not sufficiently compacted). If the rock is fragmentable, the ultimate evolution ceases with the release of the constituent grains or stones. Some also contain enough clay to make them behave in a manner similar to class R34 material.

Cut in vosgian sandstone.

b - Classification The more compact rocks are classified according to their strength in the Los Angeles fragmentation test and micro-Deval wear test, the softer rocks according to their fragmentability. LA 45 LA > 45

and or and

MDE 45 MDE > 45 FR 7

FR > 7

R5 SALINE

R41 R42 R43

ROCKS

(Gypsum, rock salt, anhydrite, etc.)

a - Description In mechanical terms, this class of materials are like class R2 and R3 but they are more soluble in water and are therefore liable to cause distress in the structure, especially when - the salt is highly soluble - it accounts for a high proportion of the rock - its fragmentability on placement is low (making the fill highly pervious).

b - Classification Soluble salt content (depending on degree of fragmentability): 5-10 % in rock salt 30-50 % in gypsum

R51

Soluble salt content (depending on degree of fragmentability): 5-10 % in rock salt 30-50 % in gypsum

R52

R6 IGNEOUS

AND METAMORPHIC ROCKS

(Granite, basalt, trachyte, andesite, etc., gneiss, schist, slate, etc.)

a - Description This class of materials may have widely differing mechanical properties. Their fragmentability and friability may be very variable (low to very high).Class R61 and R62 materials do not weather in the fill due to stresses and water but class R63 displays similar behaviour to classes R34 or R43.

13


b - Classification The more compact rocks are classified according to their strength in the Los Angeles fragmentation test and microDeval wear test, the softer rocks according to their fragmentability. LA 45 LA > 45

and or and

MDE 45 MDE > 45 FR 7

R61 R62

FR > 7

R63 Earthworks in basalt.

4.2 Soils In attempting to classify a soil on the basis of criteria capable of determining its suitability as fill and associated conditions for its placement, three parameters must be determined.

4.2.1 Grain size characteristic These characteristics are derived simply from the grain size analysis. 0/50mm fraction passing 80 μm 100%

COARSE AND POORLY STRUCTURED SOILS C1 (rounded grains or more than 60 to 80% fraction 0/50mm in the soil)

FINE SOILS A

35%

FINES-RICH SAND OR GRAVEL SOILS B5 or B6 12%

COARSE AND STRUCTURED SOILS C2 (angular grains and less than 60 to 80% fraction 0/50mm in the soil)

Passing 2mm > 70% < 70% SAND SOILS GRAVEL SOILS D1, B1, B2 D2, B3, B4 FINES-POOR 0

50mm

Dmax*

Dmax: size of largest grains

Note. A D3 class is proposed in GTR for C soils which have a methyl blue value (VBS) of less than 0.1 and less than 12 % passing the 80 μm sieve.

4.2.2 Clay characteristics These characteristics are evaluated from three tests: • Atterberg limits (plastic index Ip) • Methyl blue absorption value of soil (VBS) • Sand equivalent (ES)

Methyl Blue Test. 14


The grain size classification (section 4-2-1 above) can be completed as follows: • Fine soils 2.5

6

8

12

25

40

A1

A2

A3

VBS Ip A4

• Fines-rich sand and gravel soils 1.5

VBS

12 B5

Ip B6

• Fines-poor sand soils 0,1

0,2

VBS

35 D1

B1

ES B2

• Fines-poor gravel soils 0,1

0,2

VBS

25 D2

B3

ES B4

Note. Values in italics (e.g. 0,2) are recommended, especially for contract specifications, in preference to other limit values.

4.2.3 State characteristics Assessing the wetness of a soil (when it is “sensitive” to water) is based on its IPI value or on its natural moisture content wn at a given time in relation to the optimum moisture content wOPN determined from the standard Proctor test on the fraction smaller than 20mm, or on the value of the soil consistency index. Five hydrous states are considered: ts: (very dry) / s: (dry) / m: (normal) / h: (wet) / th: (very wet)

Soils in a very wet state.

The normal state (m) is the best condition for placement, in particular, it allows appropriate compaction to be achieved. Wet (h) and very wet (th) states are soils for which trafficability and compaction are difficult (a very wet soil is not normally trafficable for a standard earthmoving plant). The dry (s) and very dry (ts) states are soils which are difficult to compact to form stable fill structures (a very dry soil is considered as being impossible to compact properly by standard methods).

15


Soils are classified according to their hydrous state as follows. State threshold Soil type

Reference test

A1

IPI wn/wOPN IPI wn/wOPN Ic IPI wn/wOPN Ic Special study required

A2

A3

A4

ts

s 0.7 0.7 1.4 0.7 1.3

B1 B2 B3 B4 B5 B6

m 25 0.9 15 0.9 1.2 10 0.9 1.15

h 8 1.1 5 1.1 1.05 3 1.2 1

th 3 1.25 2 1.3 0.9 1 1.4 0.8

No sensivity to water content IPI wn/wOPN IPI wn/wOPN IPI wn/wOPN IPI wn/wOPN Ic

0.5

0.6 0.6 0.7 1.3

0.9

8 1.1

No sensivity to water content 15 0.9 1.1 30 12 0.9 1.1 25 10 0.9 1.1 1.2 1

4 1.25 7 1.25 5 1.25 4 1.3 0.8

Note. Values in italics (e.g. 0.9) are recommended, especially for contract specifications, in preference to other limit values, when there is a choice.

EXAMPLES

OF CLASSIFICATION

Rocks not extracted with explosives and materials displaying special behaviour • R32: argillaceous rock (e.g. classified marl or claystone), may contain carbonate fraction, the 0-50mm fraction registers less than 7 in the fragmentation test and 5-20 in the degradability test. • R41: siliceous rock (e.g. classified sandstone) with Los Angeles coefficient less than 45 and microDeval coefficient also less than 45. • Rock classified limestone with MDE greater than 45 and bulk unit weight ρd 1.84 -> class R22. Soils • A2m: fine soil with plastic index between 12 and 25 with normal moisture content (IPI between 5 and 15). • C1-B5h: soil with a fraction larger than 50mm representing less than 20-40% of whole soil sample and/or with large rounded particles. The fraction smaller than 50mm is sand or gravel with a plasticity index below 12 in the normally wet state. • C2-D2: soil with a fraction larger than 50mm representing not less than 20-40% of whole soil sample with angular particles. The fraction smaller than 50mm is clean gravel and therefore insensitive to water, so its moisture content does not need to be characterised. • Soil with: 17% passing 80μm and Dmax: 40mm -> class B5 or B6 VBS: 1,7 -> class B6 IPI: 7 -> class B6h

16


• Soil with: 55% of 0-50mm fraction passing 80 μm and Dmax: 70mm and Coarse particles (> 50mm) are rounded -> class C1-A Ip: 32 -> class C1-A3 wn/wOPN: 1 -> class C1-A3m • Soil with: 10% of 0-50mm fraction passing 80μm and 55% of 0-50mm fraction passing 2mm and Dmax: 100mm and Coarse particles (> 50mm) are angular and 48% of the complete soil sample passing 50 mm -> class C2 (D2, B3 or B4) VBS: 0.13 -> class C2-B3 Material known to be almost completely insensitive to water, so its moisture content does not need to be characterised.

4.3 Summary of classification 4.3.1 Summary table of the classification of rock and soil types Percent passing 80 μm

12

25

40

Ip

100%

A1

A2

A3

A4

35%

Soils Dmax 50mm

B5

B6

Percent passing 2 mm 100%

12%

D1

B1

B2

D2

B3

B4

70%

0% 0

0,1

0,2

1,5

2,5

6

8

0% VBS

Percent passing 80 μm fraction 0/50mm

C1 or C2 C1: poorly structured rounded or angular

Soils Dmax > 50mm

materials with fraction 0/50mm > 60-80% C2: strongly structured angular materials 12 %

with fraction D3 0

0/50mm < 60-80%

Carbonate rocks Sedimentary rocks

Rocks Igneous and metamorphic rocks

VBS

0,1

Chalk

R1

Limestone

R2

Argillaceous rocks Marls, claystone, pelite, etc.

R3

Siliceous rocks

Sandstone, puddingstone, breccia, etc. R4

Saline rocks

Rock salt, gypsum, etc.

Granite, basalt, andesite, gneiss, schist, slate, etc.

17

R5 R6

18

FINE SOILS

A

Class

Subclass by type

A4 Clay and marl clay, very high plasticity, etc.

25 < Ip ≤ 40 or 6 < VBS 8

Ip > 40 or VBS > 8

A2 Clayey fine sand, silt, low plasticity clays and marls, granite sand, etc.

A3 Clay and marl clay, high plasticity silts, etc.

12 < Ip ≤ 25 or 2,5 < VBS 6

VBS ≤ 2,5 or Ip 12

Type parameters Second level classification

Values in bold type are recommended.

Dmax 50mm and Percent passing 80μm > 35%

Type parameters First level classification Principal features

OPN

These soils are very cohesive and almost impermeable. Their moisture content is changing very slowly with large shrinkage or swelling. Their use in embankment is generally excluded, but may be resulted from a special study with eventually in-site trials.

These soils are highly cohesive at moderate to low moisture contents and sticky or slippery in the wet state making them difficult to work with on site (or in the laboratory). Their low permeability means that in-place changes in moisture content take place very slowly. Moisture content must be increased significantly before there is any significant change in consistency.

The mid-range nature of this subclass means they are suitable for use with most types of constructional plant provided moisture content is not too high. Ip is the best identification criterion.

n

Small changes in moisture content produce sudden changes in consistency, especially when w is close to w . Relatively short reaction time to changes in moisture and weather conditions but permeability may vary widely depending on grading, plasticity and compactness, so there can be a wide variation in reaction time. With low plasticity fine soils, it is frequently preferable to identify them by their methyl blue VBS value because of the lack of precision in measuring Ip.

Classification by type

A1 Low plasticity silts, loess, alluvial silts, clean fine sand, low plasticity granite sand.

FINE SOILS

Values in bold type are recommended

Class A

4.3.2 Classification according to type and state

The hydrous state thresholds can be provided by a special study.

Ic > 1,3 or wn < 0,7 wOPN

3 < IPI 10 or 1 < Ic 1,15 or 0,9 wOPN wn < 1,2 wOPN 1,15 < Ic 1,3 or 0,7 wOPN wn < 0,9 wOPN

1 < IPI ≤ 3 or 0,8 < Ic ≤ 1 or 1,2 wOPN wn < 1,4 wOPN

2 < IPI ≤ 5 or 0,9 < Ic ≤ 1,05 or 1,1 wOPN wn < 1,3 wOPN 5 < IPI 15 or 1,05 < Ic 1,2 or 0,9 wOPN wn < 1,1 wOPN 1,2 < Ic 1,4 or 0,7 wOPN wn < 0,9 wOPN Ic > 1,4 or wn < 0,7 wOPN IPI ≤ 1 or Ic ≤ 0,8 or wn 1,4 wOPN

A1th

IPI ≤ 3 or wn 1,25 wOPN 3 < IPI ≤ 8 or 1,10 wOPN wn < 1,25 wOPN 8 < IPI 25 or 0,9 wOPN wn < 1,10 wOPN 0,7 wOPN wn < 0,9 wOPN wn < 0,7 wOPN IPI ≤ 2 or Ic ≤ 0,9 or wn 1,3 wOPN

A4s

A4m

A4h

A4th

A3ts

A3s

A3m

A3h

A3th

A2ts

A2s

A2m

A2h

A2th

A1s A1ts

A1m

A1h

Subclass

Parameters and limit values

Classification by state


19

SAND AND GRAVEL SOILS WITH FINES

B

Class

B2 Clayey sand (low clay content), etc.

B3 Silty gravel, etc.

- Percent passing 80 μm 12 % - Percent passing 2 mm 70 % - 0.1 ≤ VBS ≤ 0.2 or ES > 25

B1 Silty sand, etc.

Subclass by type

- Percent passing 80 μm 12 % - Percent passing 2 mm > 70 % - VBS > 0.2 or ES 35

- Percent passing 80 μm 12 % - Percent passing 2 mm > 70 % - 0.1 ≤ VBS ≤ 0.2 or ES > 35


B2ts

B2s 0,5 wOPN wn < 0,9 wOPN

wn < 0,5 wOPN

B2m

0,9 wOPN wn < 1,10 wOPN

Sandy material usually insensitive to water, but this must be confirmed (by extra studies, trial embankment, etc.) in some cases (material extracted from below the water table, etc.). Their use as capping layer material without treatment with hydraulic binders requiry prior measurement of their mechanical strenght (LA and MDE tests).

Their use as capping layer material without treatment with hydraulic binders requires prior measurement of their mechanical strength (sand friability FS).

When extracted from below the water table and stockpiled, they remain “wet” to “very wet”, they are unlikely to become “normal” in an oceanic climate.

B2 h

B32

B31

LA 45 and MDE 45 LA > 45 or MDE > 45

B22ts

B21ts

FS 60 FS > 60

B22s

B21s

FS 60 FS > 60

B22m

B22h FS > 60

4 < IPI 8 or 1,10 wOPN wn < 1,25 wOPN

FS > 60

B21h

FS 60

Short reaction time to changes in moisture and weather conditions but can vary widely (depending on permeability).

B21m

B22th

FS 60

B21th B2th

FS > 60

IPI 4 or wn 1,25 wOPN

FS 60

The plasticity of the fines makes these soils sensitive to water.

B12

B11

Parameters and limit values Subclass

FS > 60

Subclass

Mechanical strength (sand friability FS) must be tested before use in capping layers.


Classification by behaviour

FS 60

Principal features


Sandy material usually insensitive to water, but this must be confirmed (by extra studies, trial embankment, etc.) in some cases (material extracted from below the water table, etc.).


CLASSIFICATION LEVEL NECESSARY FOR USE IN CAPPING LAYERS

CLASSIFICATION LEVEL NECESSARY FOR USE IN EMBANKMENTS



Dmax 50mm and Percent passing 80μm 35%

Type parameters First level classification

Class B


20


B

Class

SAND AND GRAVEL SOILS WITH FINES (cont'd)

- Percent passing 80 μm between 12 and 35% - VBS > 1.5 or Ip > 12

- Percent passing 80 μm between 12 and 35% - VBS ≤ 1.5 or Ip 12

- Percent passing 80 μm 12% - Percent passing 2 mm 70% - VBS > 0.2 or ES < 25

Clayey to very clayey sand and gravel

B6

Very silty sand and gravel, etc.

B5

Clayey gravel (low clay content), etc.

B4

Subclass by type Principal features

The influence of the fines is preponderant. The soil behaves similarly to fine soil having the same plasticity as the soil fines but with greater sensitivity to water due to the higher proportion of sand.

The proportion and low plasticity of fines in these soils make them behave much like A1 soils. For the reason mentioned in connection with A1 soils, it is preferable to use the VBS criterion rather than Ip for identification purposes. Their use as capping layer material without treatment with hydraulic binders requires prior measurement of their mechanical strength (LA test and/or micro-Deval in presence of water).

Plastic fines make these soils sensitive to water. They contain more gravel than B2 soils and less sand, so they are generally pervious. They react quite quickly to changes in the water and climatic conditions (wetting and drying). When extracted from below the water table, it is unlikely for their moisture state to improve to “normal.” Their use as capping layer material without treatment with hydraulic binders requires prior measurement of their mechanical strength (LA test and/or micro-Deval in presence of water).


wn < 0,7 wOPN or Ic > 1,3

B6ts

B6s

0,7 wOPN ≤ wn < 0,9 wOPN or 1,2 < Ic 1,3

B6m

B6 h

B6th

B5ts

B5s

B5m

B5 h

B5th

B4ts

B4s

B4m

B4 h

B4th

Subclass

10 < IPI 25 or 1 < Ic 1,2 or 0,9 wOPN ≤ wn ≤ 1,1wOPN

or 1,1 wOPN wn < 1,3 wOPN

4 < IPI ≤ 10 or 0,8 < Ic 1

or Ic 0,8

IPI ≤ 4 or wn 1,3 wOPN

wn < 0,6 wOPN



12 < IPI 30 or


5 < IPI ≤ 12 or


wn < 0,6 wOPN




7 < IPI ≤ 15 or








Dmax 50mm and Percent passing 80μm 35%


Class B (cont'd)

LA 45 and MDE 45 LA>45 or MDE>45 LA 45 and MDE 45 LA>45 or MDE>45

LA 45 and MDE 45 LA>45 or MDE>45

B52m B51s B52s B51ts B52ts

B52h B51m

B41m B42m B41s B42s B41ts B42ts B51th B52th B51h

LA 45 and MDE 45 LA>45 or MDE>45 LA 45 and MDE 45 LA>45 or MDE>45 LA 45 and MDE 45 LA>45 or MDE>45 LA 45 and MDE 45 LA>45 or MDE>45 LA 45 and MDE 45 LA>45 or MDE>45

B42h

LA>45 or MDE>45

B41h

B41th B42th

LA 45 and MDE 45 LA>45 or MDE>45 LA 45 and MDE 45

Subclass




Dmax > 50mm


Class C

21

Soils containing fine and coarse particles

C

Class

C2Ai Flint clays, gritstone clays, scree, flint deposits, etc.

C2Bi Flint clays, gritstone clays, scree, flint deposits, etc.

Angular material with 0-50mm fraction < 60-80 %. The 0-50mm fraction is a class B or D soil

Flint clays, gritstone clays, scree, moraine, coarse alluvium, etc.

C1Bi

C1Ai Flint clays, gritstone clays, scree, moraine, coarse alluvium, etc.

Subclass by type

Angular material with 0-50mm fraction < 60-80 %. The 0-50mm fraction is a class A soil

Angular material with 0-50mm fraction exceeding 60-80 % or Rounded materials. The 0-50mm fraction is a class B or D soil

Angular material with 0-50mm fraction exceeding 60-80 % or Rounded materials The 0-50mm fraction is a class A soil



The behaviour of these soils is governed by the 50-D fraction also and cannot be assessed from the behaviour of the 0-50mm fraction alone. The extent of this influence is always difficult to assess (depending on the continuous grading of the material and the angularity of the coarser particles) because of practical difficulties involved in performing laboratory tests on these materials. However, as for class C1, it is useful to use a double identification symbol, e.g. C2(A1) or C2(B1) where A1 and B1 shows the class of the 0-50mm fraction. Large-scale or full-scale tests are frequently needed to guide interpretation of test results on the 0-50mm fraction.

The behaviour of this class can be adequately assessed from the behaviour of the 0-50mm fraction. The proportion of 0-50mm particles must be evaluated when the soil consists of angular particles. This can be done by eye by an experienced geotechnician when Dmax exceeds 200mm. The soils in this class must be identified by a double symbol, e.g. C1(A1) or C1(B1), where A1 and B1 show the class of the 0-50mm fraction in the C1 soil. For example, a soil classified as C1(A3) is a rounded or angular soil with more than 60-80% of particles smaller than 50mm with a 0-50 mm fraction classed as A3.

Principal features

C2A1 C2A2 C2A3 C2A4 C2B11 C2B12 C2B31 C2B32 C2B21 C2B22 C2B41 C2B42 C2B51 C2B52 C2B6 C2D1 C2D2

C 1 A1 C 1 A2 C 1 A3 C 1 A4 C1B11 C1B12 C1B31 C1B32 C1B21 C1B22 C1B41 C1B42 C1B51 C1B52 C 1 B6 C1D1 C1D 2

Materials not sensitive to moisture state

State th, h, m, s or ts

Material generally not sensitive to moisture state

State th, h, m, s or ts

Subclasses in class C are as follows.

The subclass classification of these soils on the basis of their moisture state must refer to their 0-50mm fraction, which may be class A or B.

Classification by state and behaviour

SOILS CONTAINING FINE AND COARSE PARTICLES


VBS 0.1 and percent passing 80 μm 12 %


Class D

22

Soils not sensitive to water

D

Class

Dmax < 50mm and percent passing 2mm 70 %

Dmax < 50mm and percent passing 2mm > 70 %


Clean alluvial gravel, coarse sand, etc.

D2

Clean alluvial sand, dune sand, etc.

D1

Subclass by type


These are cohesionless pervious soils. Erosion resistance and trafficability are better if the compacted material is well graded.

These are cohesionless pervious soils. Often fine grained and poorly graded, they are highly erodible and have poor trafficability.

Principal features

Limit values

LA > 45 or MDE > 45

LA 45 and MDE 45

FS > 60

FS 60


Their use as capping layer material without treatment with hydraulic binders requires prior measurement of their mechanical strength (LA test and/or micro-Deval in presence of water or sand friability).



SOILS NOT SENSITIVE TO WATER

D22

D21

D12

D11

Subclass


Sedimentary rocks

Carbonate rocks

R2 Miscellaneous calcareous rocks e.g. - coarse grained limestone - travertine - tufa and hardpan, etc.

R1 Chalk

Principal features

23

This class comprises the whole range of calcareous rock materials. Their predominant characteristics with respect to their use in embankments and capping layer are their friability and, with some fragmentable types, their frost susceptibility. In general, these materials are not evolutive rock materials and raise no special problems in embankments. When used as capping layer material, attrition or crumbling may produce fines, making the material sensitive to water.

Chalk is made of calcite grains 1-10 μm in size. The structure of the mass is fragile, more so when porosity is high (or conversely, when dry density is low). Tests and field experience have shown that earthmoving operations produce large amounts of fines, directly related to the fragility of the structure. When chalk is near-saturated or completely saturated, the pore water reaches these fines and forms a paste which soon invades the whole material, preventing traffic of construction plant and generating pore pressures in the structure. Conversely, at low moisture contents, chalk is a rigid material with high bearing capacity but compaction is difficult. Some low density, very wet chalks may continue to fragment after placement, mainly due to applied stresses and frost.


R11

R21

R22

R23

Hard limestone

Moderately dense limestone Fragmentable limestone

MDE > 45 and ρd > 1.8

ρd 1.8

ρd 1.5 and wn < 16 MDE 45

R13s R13ts

ρd 1.5 and 16 wn < 21

R13m

R13h

ρd 1.5 and 26 wn < 31 ρd 1.5 and 21 wn < 26

R13th

ρd 1.5 and wn 31

R12s

R12m

R12h

1.5 < ρd 1.7 and wn < 18

Loose chalk

Moderately dense chalk

Dense chalk

Subclass

R12ts

1.5 < ρd 1.7 and 18 wn < 22

1.5 < ρd 1.7 and 22 wn < 27

1.5 < ρd 1.7 and wn 27

ρd > 1.7



ROCK MATERIALS (evolutive and non-evolutive)

Petrographic type of rock

Class R


24

Saline rocks

Siliceous rocks

R5 Gypsum Rock salt Anhydrite

R4 Sandstone Puddingstone Breccia

FR 7 and DG > 20


FR > 7

LA > 45 or MDE > 45 and FR 7

LA 45 and MDE 45

Soluble salt content In mechanical terms, this class of materials is similar to class R2 and 5-10% for rock salt* R3 but they are more or less soluble in water, with risks of distress in 30-50% for gypsum* the structure; the risk is greater when - salt solubility is high Soluble salt content - the proportion of soluble salt is high > 5-10% for rock salt* - its fragmentability on placement and compaction is low (producing > 30-50% for gypsum* highly pervious fill). *depending on fragmentation potential

This class of material can be likened to a conglomeration of sand grains (as with sandstone) or stone (breccia and puddingstone) cemented together by silica or calcite. The strength of the cement is variable, making the behaviour of these materials variable (with a risk of post-placement rearrangement if inadequately compacted). If the rock is very fragmentable, its ultimate stage of evolution might be the individual grains. Some materials contain enough clay to make behaviour similar to class R34.

FR > 7 and wn < 0.7 wOPN

The characteristic feature of this class of materials is that they possess a (usually carbonate) structure of varying strength, FR 7 and 5 < DG 20 imprisoning a variable proportion (5-95% in the generally accepted FR 7 and DG 5 view) of clay minerals which may swell. They fragment to varying degrees when worked, producing plastic, water sensitive fines. FR > 7 and wn 1.3 wOPN Collapse of the rock structure may continue after completion of the or IPI < 2 works due to applied stresses, water and frost. This evolutive effect FR > 7 and 1.1 wOPN wn < 1.3 wOPN is more pronounced when there has been less fragmentation of the or 2 ≤ IPI < 5 material during construction and grading is uniform at this stage. FR > 7 and 0.9 wOPN wn < 1.1 wOPN For the more fragmentable (class R34), the state of the 0-50mm FR > 7 and 0.7 wOPN wn < 0.9 wOPN fraction must be characterised.

Principal features

R33

Argillaceous rock, low fragmentation, low degradability

High solubility saline rocks

Low solubility saline rocks

Fragmentable siliceous rock

Moderately hard siliceous rocks

Hard siliceous rocks

Crumbly, argillaceous rock

R32

Argillaceous rock: low fragmentation, middle degradability

R52

R51

R43

R42

R41

R34s R34ts

R34m

R34h

R34th

R31

Argillaceous rock: low fragmentation, high degradability

Subclass


ROCK MATERIALS (cont’d) (evolutive and non-evolutive)


R3 Marl Shale Claystone Pelite


Sedimentary rocks

Argillaceous rocks


Class R (cont’d)


Igneous and metamorphic rocks

The materials in this class may display very different mechanical characteristics; in particular, their fragmentability and friability can vary widely (from low to very high). R61 and R62 materials do not weather in the fill from applied stresses and water but the behaviour of class R63 is close to class R34 and R43 behaviour.

Principal features

R62

R63

Crumbly or weathered igneous and metamorphic rocks

FR > 7

R61

Moderately hard igneous and metamorphic rocks

Hard igneous and metamorphic rocks

Subclass

LA > 45 or MDE > 45 and FR 7

LA 45 and MDE 45



ROCK MATERIALS (cont’d) (evolutive and non-evolutive)


Granite, basalt, trachyte, andesite, etc. Gneiss, schist, slate, etc.

R6


Class R (cont’d)


25

Use of soils and rocky materials in embankment construction • Use of rocks and soils in embankment construction

5. Use of rocks and soils in embankment construction The following conventional definitions are used in this section. Weather ++ means + means = means means

heavy rainfall light rainfall weather conditions free from any significant rainfall or evaporation weather conditions causing significant evaporation.

Conditions of use • h ≤ is an engineering requirement setting a limit on the height of the embankment at the maximum height specified (if no value is specified, embankments more than around 15m high must have their stability checked by a soil mechanics type of approach. Deformability of the embankment foundation soil has to be checked in addition. • sprinkling is an engineering requirement for the material to be wetted to maintain its natural moisture content within the envelope applicable to the initial state classification. • moisture correction means action to Binder spreading plant. maintain, reduce or increase the natural moisture content of a soil having a good moisture content despite weather conditions; if the soil is too wet, this means benefiting from evaporative weather conditions and for a dry soil, exposing the soil to rainfall in wet weather, using appropriate field techniques such as windrowing, excavation in thin layers, blending, slow placement rates, etc. • protection is the opposite action, to keep soil moisture near its initial value by placement in the structure quickly after excavation, protecting excavation bench faces against evaporation or rainfall as appropriate (vertical or steep working faces), early compaction to seal the surface, drainage and sealing, etc. • treatment, usually with lime but sometimes with other binders, renders some over-wet soils suitable for use as a constructional material. A special study must always be made to determine the benefits and feasibility of treatment, application rates, and associated difficulties if any6. Plough mixing a wet clay with hot lime.

6. Details can be found in the Technical Guidelines on Treatment of Soils with Lime and/or Other Hydraulic Binders as Applied to the Construction of Embankments and Capping layers, issued by LCPC - SETRA, Jan. 2000.

26


The above five conditions can be met with various strategies appropriate to site-specific conditions. Compliance is ensured by respecting with the maximum embankment height specified for the relevant material (first condition), changing moisture content of the material as measured at the time of compaction (next two conditions), and respecting application rate and mixing of the binder (last condition). Compaction conditions Compaction intensity yields a qualitative indication of the compaction energy needed to produce a stable embankment for a given soil. Layer thickness is a qualitative indication of the thickness of individual layers of the fill to be compacted before placing the next layer. Warning: The specified layer thickness sets a limit on the size of the individual soil particles. With the largest compaction plant available today, the largest acceptable particle size in fill must not be larger than 800mm. Section 3 hereafter gives precise quantitative values to be complied with in order to achieve a satisfactory degree of soil compaction in the fill. Failure to comply with any of the requirements in the following table may have serious consequences which must be assessed as necessary. Embankments higher than 15m and materials with a Dmax in excess of 800mm fall outside the scope of this Manual.

5.1 Rock and materials displaying special behaviour CHALK R1 Compaction Soil class R11

R12h

R12m,s and ts R13th R13h

R13m R13s

R13ts

Weather

Use

++ + = or -

no yes yes

+ = =

no yes yes

-

yes yes

++ +, = and -

no yes

+ or = = -

no no yes yes yes

+ = or + = or -

no yes no yes

Requirements for use

Compaction intensity

Layer thickness

moderate intense

moderate moderate

treatment h 5m

moderate moderate

moderate

treatment moisture correction; h 10m

intense moderate

moderate thin

h 10m

intense

moderate

treatment treatment moisture correction; h 5m

moderate intense moderate

moderate moderate moderate

intense

thin

intense

thin

h 10m

no

27

Remarks

Full-depth excavation recommended to prevent excessive crushing of the chalk

Excavation in thin layers recommended to improve subsequent compaction of the chalk


CALCAREOUS Soil class R21, R41, R61

ROCKS

Weather ++, +, = and -

R2,

Use

SILICEOUS ROCKS Requirements for use

yes

R4,

IGNEOUS AND METAMORPHIC ROCKS

Compaction Compaction Layer intensity thick

See soil classes obtained on site (cf. conditions of use below)

ARGILLACEOUS Soil class

Weather

R31

R33

R34th R34h

R34m

R34s

R34ts

Remarks

moderate

R22, R23, R42, R43, R62, R63

R32

R6

ROCKS

Use

R3 Requirements for use

Compaction Compaction Layer intensity thick

Remarks

no ++ +

no yes

= or -

yes

= or -

yes

++ + = or -

no yes yes

+ =

no no yes

=

yes

-

yes

-

yes

++ +

no yes

= or -

yes

++ +

no yes

=

yes

-

no no

extra fragmentation after extraction ; h 10m

intense

thin

extra fragmentation after extraction ; h 5m extra fragmentation after extraction, sprinkling ; h 10m

intense

thin

further thought needed on field fragmentation method and embankment design as above

intense

thin

as above

moderate intense

moderate moderate

as above as above

moderate

moderate

as above

moderate

thin

as above

moderate

moderate

as above

intense

moderate

as above

thin

as above

thin

as above

treatment with lime alone extra fragmentation after extraction ; h 5m moisture correction ; extra fragmentation after extraction ; h 10m treatment with lime alone extra fragmentation after extraction ; h 10m extra fragmentation after extraction ; h 10m

moderate

moderate

moisture correction ; intense extra fragmentation after extraction ; h 5m sprinkling ; extra intense fragmentation after extraction ; h 5m

28


SOLUBLE

ROCKS

R5 Compaction

Soil class

Weather

Use



Layer thickness

R51

R52

Remarks

Conditions of use of these rock materials in fill are similar to those for class R2 if the rock contains little clay, or for class R3 otherwise Rocks too soluble for use in fill

no

5.2 Soils Compaction Soil class A1th A1h

A1m

A1s

Weather

Use

+ = -

no no yes yes yes

-

yes

++ + = -

no yes yes yes yes

++ +

no yes

= -

yes yes

A1ts

A2m

A2s

A2ts


treatment h 5m moisture correction ; h 10m treatment

moderate low moderate

protection ; h 10m

moderate moderate moderate intense

sprinkling h 10m

Layer thickness

thin

moderate

moisture correction ; h 10m h 10m sprinkling ; h 5m

moderate

treatment with lime h 5m moisture correction ; h 10m treatment with lime

low low moderate

thin

intense intense

no

A2th A2h


no + = = -

no yes yes yes

-

yes

++ + = -

no yes yes yes yes

++ +

no yes

= -

yes yes

protection ; h 10m sprinkling h 10m moisture correction ; h 10m h 10m sprinkling ; h 5m

thin

moderate moderate moderate moderate intense intense intense intense

no

29

thin

Remarks


Soil class

Weather

A3th A3h

A3m

A3s

Use

++ + = = -

no yes yes yes yes yes

++ + or = -

no yes yes yes

++ +

no yes

= -

yes yes no

A4

no

B2th B2h

B2m

B2s

++ +, = or -

no yes

+ = = -

no no yes yes yes

-

yes

+ = -

no yes yes yes

++ +

no yes

= -

yes yes

B2ts

no

B3

yes

B4th B4h

B4m

Compaction Compaction Layer intensity thickness

no

A3ts

B1


h 5m treatment with lime h 5m treatment with lime moisture correction ; h 10m

low moderate low moderate moderate

h 10m sprinkling ; h 10m h 5m

moderate moderate intense

moisture correction ; intense h 5m sprinkling ; h 5m intense protection ; sprinkling ; intense h 5m

thin

thin

thin thin thin

moderate

treatment h 5m moisture correction ; h 10m moisture correction and treatment

sprinkling moisture correction ; h 10m h 10m sprinkling ; h 10m


thin

moderate

moderate intense moderate intense

thin

intense intense

moderate

no + = = -

no yes yes yes

-

yes

++ + = -

no yes yes yes yes

treatment h 10m moisture correction ; h 10m treatment


protection ; h 10m

moderate moderate intense moderate

sprinkling

moderate

30

thin

Remarks


Soil class B4s

B4ts B5th B5th B5h

B5m

B5s

++ + = -

no yes yes yes

moisture correction h 10m sprinkling ; h 10m

intense intense intense

+ + = = -

no no no no yes yes yes

treatment h 5m moisture correction


-

yes

moisture correction and treatment

moderate

++ + = -

no yes yes yes yes

protection ; h 10m

moderate moderate moderate intense

++ +

no yes

= -

yes yes no

B6th

no

B6m

B6s

B6ts


Use

B5ts

B6h


Weather

+ =

no yes

= -

yes yes

-

yes

++ + = -

no yes yes yes yes yes

++ +

no yes

= -

yes yes yes

sprinkling

moisture correction ; intense h 10m h 10m intense protection, sprinkling ; intense h 10m

treatment with lime alone h 5m moisture correction ; h 10m treatment with lime alone protection ; h 10m h 10m sprinkling protection moisture correction ; h 10m h 10m sprinkling ; h 5m sprinkling ; protection ; h 10m

thin

thin

thin


thin

moderate

moderate moderate intense moderate intense intense intense intense intense

no

31

Remarks

thin

layer excavation recommended


Soil class

Weather

C1A1th

Use



no

C1B5th C1A1h

+

no

=

yes

C1B5h

C1A1m

treatment after removing particles larger than 250mm

moderate

= or -

yes

h 5m

low

-

yes

moisture correction

moderate

protection ; h 10m

moderate

++

no

+

yes

=

yes

-

yes

-

yes

C1A1s

++

no

C1B5s

+

yes

h 5m

intense

+

yes

moisture correction ;

intense

C1B5m

thin

moderate intense sprinkling

moderate

thin

h 10m =

yes

h 10m

intense

-

yes

sprinkling ; h 10m

intense

C1A1ts

no

C1B5ts C1A2th

no

C1A3th C1B6th C1A2h

++

no

+

yes

protection ; h ≤ 5m

low

=

yes

h ≤ 5m

low

=

yes

treatment with lime alone after removing particles larger

moderate

-

yes

moisture correction ; h 10m

moderate

++

no

+

yes

protection ; h 10m

moderate

=

yes

-

yes

-

yes

C1A3h C1B6h

than 250mm

C1A2m C1A3m C1B6m

moderate intense sprinkling

moderate

32

thin

Remarks




Soil class

Weather

Use

C1A2s

++

no

+

yes

h 5m

intense

+

yes

moisture correction ; h 10m

intense

=

yes

h 5m

intense

-

yes

sprinkling: h 5m

intense

C1A3s C1B6s

C1A2ts

no

C1A3ts C1B6ts C1A4

no

C1B1

yes

moderate

C1B3 C1B2th

no

C1B4th C1B2h

+

no

=

yes

treatment after removing particles larger than 250mm

moderate

=

yes

h ≤ 10m

low

-

yes

moisture correction

moderate

++

no

+

yes

protection

moderate

+

yes

h ≤ 10m

=

yes

moderate

-

yes

intense

-

yes

++

no

C1B4h

C1B2m

thin

C1B4m

C1B2s

sprinkling

moderate

moderate

C1B4s +

yes

moisture correction

intense

=

yes

h ≤ 10m

intense

-

yes

sprinkling ; h 10m

intense

C1B2ts C1B4ts

no

33

thin

Remarks


Soil class

Weather

C1D1

Use


yes

Compaction Compaction Layer intensity thickness moderate

C1D2 C2A1th

no

C2B2th C2B4th C2B5th C2A1h

++

no

+

yes

h ≤ 5m

moderate

=

yes

h ≤ 10m

moderate

-

yes

moisture correction

moderate

++

no

+

yes

moderate

=

yes

moderate

C2B2h C2B4h C2B5h

C2A1m

moderate

C2B2m C2B4m C2B5m

C2A1s

-

yes

-

yes

intense

++

no

+

yes

=

yes

h 10m

intense

-

yes

sprinkling ; h 10m

intense

sprinkling

moderate

C2B2s C2B4s C2B5s

C2A1ts

intense

no

C2B2ts C2B4ts C2B5ts

34

moderate moderate

Remarks


Soil class

Weather

C2A2th

Use



no

C2A3th C2B6th C2A2h

+

no

=

yes

h ≤ 10m

low

moisture correction

moderate

h 10m

moderate

C2A3h C2B6h

C2A2m

-

yes

++

no

+

yes

thin

C2A3m C2B6m

C2A2s

=

yes

moderate

-

yes

intense

-

yes

++

no

+

yes

sprinkling

moderate

moisture correction

intense

C2A3s C2B6s

C2A2ts

=

yes

h 10m

intense

-

yes

sprinkling ; h 10m

intense

no

C2A3ts C2B6ts C2A4

no

C2B1

yes

moderate

yes

moderate

yes

moderate

C2B3 C2D1 C2D2 D1 and D2

35

moderate

Remarks

Use of soils and rocky materials in embankment construction • Compaction of fill

6. Compaction of fill 6.1 Definition of specifications The GTR method recommended in this Manual has the particular advantage of stating the means of compaction required of compaction of fill. They are effectively described by specifying the plant and resources to be used, rather than by the standard approach of stipulating results whose determination is too uncertain. Where a soil is suitable for the Proctor test (i.e. soils containing less than 30 % particles larger than 20mm), it has been possible to determine the objectives of densification by compaction of the constituent layers of fill, i.e. • dry unit weight averaged over the whole thickness of the compacted layer equal to or greater than 95 % of the maximum dry unit weight from the standard Proctor test • dry unit weight over the bottom 8 centimetres of the compacted layer equal to or greater than 92 % of the maximum dry unit weight from the standard Proctor test, but this is not true for coarser materials not covered by the Proctor test. With such materials, it is impossible to specify densification objectives or to measure the in-place density achieved by any simple test. Even with soils suitable for such testing, monitoring the results obtained on the completed embankment or on each layer by measuring the in-place bulk unit weight usually involves many difficulties such as: - the need for a reference value for the bulk unit weight (generally a percentage of the standard Proctor density), - the difficulty of measuring the in-place density achieved (mainly because density varies over the thickness of the compacted layer), - the discrete nature of measurements and their statistical interpretation. Continuous compaction monitoring (section 6-4) has the merit of being based directly on compaction “specifications” which, provided they have a scientific foundation backed up by experience (see tables in section 6-3-2), guarantee the quality of the works at a compaction cost which the contractor can estimate quite closely before commencing the works. The GTR classification system according to type and state describes soil classes such that, within each class, the densification energy needed to obtain a stable fill is roughly the same. In this way, the compaction energy can be set beforehand for each specific job, along with appropriate construction method (see tabulated data in section 5 above). The next step is to classify the compaction plant according to its performance, with reference to the principles set forth in section 6-2 below. These two items are used in the tables in section 6-3 below in which the required compaction energy is expressed by two parameters: • maximum thickness (compacted thickness, not bulked thickness) of constituent layers of fill • Q/S ratio in m3 per m2, a measure of the ratio between the compacted soil volume placed in a given time (say, one day) Q, and the area of fill covered by the compaction machine in the same time S. Volume Q is calculated from the number of round trips by haulage plant of known capacity or beforehand from the estimated geometrical volume of the embankment to calibrate the haulage plant. Area S is obtained from the effective width of the compaction machine multiplied by the distance covered by the machine, usually read from the mileage counter or, better, from a tachograph fitted to the machine. If there are restrictions on machine use, such as a maximum forward speed, this information appears in the table in section 6-3. Controlled trials were the basis for drawing up the tables in section 6-3 below and for checking that compliance with: • the stipulated maximum compacted layer thickness, • the requirement that the Q/S ratio effectively obtained on the job is equal to or less than the stipulated Q/S ratio, and

36


• the compaction machine class (ballast, weights and speed of the eccentrics in vibrating rollers) and any type-specific restrictions, is an a priori assurance of the quality of the work. Since it is the method which is stipulated, there must be no stipulations on final in-place density obtained (if possible) written into the contract, because of the problem of the accuracy of the reference tests, in order to avoid ambiguities.

6.2 Classification of compaction plant Refers to French standard NF P 98-736. Basic principles are set forth below. • Classification and use The rollers considered have a compaction width of 1.30m or more. Classification and conditions of use of small compacting equipment (vibratory rollers, vibrating plates, tampers) is detailed in the Technical Guidelines “Trench Backfill and Carriageway Repair” [SETRA-LCPC Ed. (May 1994)]. However, the most efficient vibrating plate compactors are included. The basic types of compacting plant addressed are: - pneumatic tyred rollers Pi - smooth vibrating drum rollers Vi A pneumatic tyred and a vibrating tamping rollers. - tamping rollers VPi - static tamping rollers SPi - vibrating plate compactors PQi. i is the class number; it increases with compaction efficiency within each type category. Combination types are dealt with in section 6-2-3 below.

6.2.1 Pneumatic tyred rollers (Pi) • Classification is based on load per wheel CR P1: P2: P3:

CR between 25 and 40 kN CR between 40 and 60 kN CR greater than 60 kN

Pneumatic tyred rollers can be ballasted to obtain the maximum wheel load recommended by the manufacturer. They can usually be ballasted to twice their empty weight. Research into maximum efficiency indicates that the highest wheel load compatible with trafficability should be used. Where a roller falls into more than one class, the classification used should be selected with reference to the effective wheel load used on the job. For best efficiency, it is also recommended that tyres be inflated to the highest pressure compatible with trafficability. Maximum forward speed is limited only by consideration of driving safety.

6.2.2 Smooth vibrating drum rollers (Vi) • Classification and use Smooth vibrating drum rollers are classified according to parameter (M1/L) ¥A0 and a minimum A0 value. M1/L7 expressed in kg/cm and A08 in mm lead to the five classes in the following table and the nearby figure. 7. M1 is the total mass (in kg) acting on the full width of the vibrating or static drum. L is the width (in cm) of the vibrating or static drum 8. A0 is the theoretical empty amplitude calculated as A0 = 1000 (me/M0) in which me is the eccentric moment (in mkg) and M0 is the mass (in kg)of the vibrating part excited by the eccentric.

37

Single drum

CLASSIFICATION OF VIBRATING ROLLERS


38


V1

(M1/L) x ¥A0

{ between 15 and 25 { greater than 25

and and

A0 0.6 A0 between 0.6 and 0.8

V2

(M1/L) x ¥A0

V3

(M1/L) x ¥A0

V4

(M1/L) x ¥A0

{ { { { { {

and and and and and and

A0 A0 A0 A0 A0 A0

V5

(M1/L) x ¥A0

{ greater than 70

and

A0 1.6

between 25 and 40 greater than 40 between 40 and 55 greater than 55 between 55 and 70 greater than 70

0.8 between 0.8 and 1.0 1.0 between 1.0 and 1.3 1.3 between 1.3 and 1.6

A0 can be tested by the “cushion” method described in French standard NF P 98-761 “Verification Test of Moment of Vibrating Roller Eccentrics.” Many vibrating rollers have more than one empty nominal amplitude value (by changing eccentric moment) and/or, less frequently, can be ballasted. This may cause machines to appear in more than one class according to their A0 and/or M1/L value.

Vibrating rollers are assumed to operate at the maximum frequency set by the manufacturer for a given eccentric system. Except for classes V1 and V2, a range of forward speeds is assumed, with a bearing on compaction practice (Appendix 4.1.2). However, while high speeds are attractive in that they speed up work rates, this is only permitted with machines fitted with a speedometer on the instrument panel and a recording system for monitoring purposes. • Single and tandem drum rollers The two most common types are single drum designated VMi and tandems, VTi (Vi is the efficiency class defined above).

Empty amplitude A0 can be measured with a vibrograph while vibrating the roller on air-filled cushions (French standard NF P 98-761).

- Category VMi contains all single vibrating drum types, twin drum types (two drums on the same axle) and tandems in which only one drum vibrates. Tables (e, Q/S) are directly applicable to these types. - Category VTi is for tandems with two vibrating drums. In most cases, the efficiency class is the same for both the front and rear drums. Compared to single drum types, the Q/S and number of load applications are the same, but the number of passes is halved.

Class VM4 single smooth vibrating drum roller.

39


6.2.3 Vibrating Tamping rollers (VPi) Tamping rollers are mostly derived from smooth vibrating drum rollers discussed in section 6-2-2 above, and are classified on the same criteria. Compaction methods only differ from smooth drum rollers in class VP3 and beyond. They seek to extract the most benefit from both vibration and the tamping feet. The tamping rollers in the compaction tables are single drum types designated VPi in French standard NF P 98-736.

6.2.4 Static Tamping rollers (SPi) Static tamping rollers are classified according to the average static load per unit width of drum(s) with tamping feet. SP1: M1/L between 30 and 60 kg/cm SP2: M1/L greater than 60 kg/cm but less than 90 kg/cm Machines with provision of ballasting are classified according to their configuration on site. They should be driven at maximum allowed speed and final compaction should be done at 10-12 kph. The first passes should generally be made at distinctly slower speeds but never less than 2-3 kph. The time that rollers fitted with a blade spend as bulldozers and graders is not considered compaction time.

SP1 static tamping roller. When used as a grader as in the photograph, it is not considered.

If average speed recorded on site (which should not be less than 6 kph) is less than the average shown in the compaction tables, this fact must be considered to recalculate the rate.

Tandem rollers frequently have the same Q/S and number of load applications as single drum types (values in table). The number of passes must be halved.

6.2.5 Vibrating plate compactors (PQi) All plate compactors are classified as PQ1 to PQ4 in the Technical Guidelines on Trench Backfill and Carriageway Repair. [SETRA - LCPC Ed. /May 1994] They are classified on the basis of the static pressure under the plate Mg/S in kPa (Mg is the weight of the plate). The smallest plates PQ1 and PQ2 are ignored. Those included are PQ3: Mg/S between 10 and 15 kPa PQ4: Mg/S greater than 15 kPa. S is the contact area between plate and soil, not the overall area. S varies on models which can be fitted with extensions and this may alter the classification.

40


6.3 Compaction specifications 6.3.1 Use of tables - Examples of application * Classes Pi, V1, V2, VPi, SPi and PQi (single column) Example: B1 soil in embankment (quality q4) Method Code 2

Class P1 Q/S

Applicable code e comes from soil V use tables (based on moisture N content and weather) Q/L

0.060

Same value (in m) for all thicknesses

0.35 5.0

Actual compacted thickness e < e (in m) V is max speed for vibratory plant, average speed for other plant (in kph)

6

Number of load applications: rounded up from actual thickness/(Q/S) given for e of the table If e = 0.30, then N = 5

300

Rate per metre width Q/L = 1000 x V x (Q/S) Practical rate of compacting operations with an efficiency ratio k (between 0.5 et 0.75) Qpract = k x (Q/L x L x (N/n) If k = 0.6 L = 2m N/n = 1, then Qpract = 360 m3/hr

* Classes V3 to V5 (double columns: possible envelope) Example: B1 soil in embankment Method Code 2

Class V3 Q/S

0.135

e

0.30

0.80

V

5

2

N

3

6

Q/L

675

270

Same value for all combinations of thickness and speed Right column: choice of low V 2.0 kph to maximise e (0.80m) Left column: max rate with high V limited to 5 kph max and e set at 0.30m Same design rules as before in each column

It can be seen that a higher forward speed is necessarily associated with a lesser layer thickness because of the steeper density gradient in the layer. Providing these conditions are complied with, the compaction rate is still higher. It is of course unacceptable to mix values from both columns (greatest thickness and highest speed).

41


If the nominal thickness e for the job (ejob) falls between the above two values, optimum compaction conditions can be calculated as follows: - average vibrating roller speed calculated from V x e = constant (values considered are taken from the right hand column: V min and e max) V=

Vxe ejob

- Q/L calculated with Q/L = 1000 x V x Q/S - N is always taken as equal to ejob/ (Q/S) The values calculated in this way are then used as requirements as if they came directly from the tables. In the above example, if the planned layer thickness for the job is 0.50m, V is defined as Method Code 2

V3 Q/S

0.135

e

0.50

V

3

V = (0.80 x 2)/0.5 = 3.2 rounded off to 3

N

4

N = 0.5 / 0.135 = 3.7 rounded off to 4

Q/L

405

Q/L = 1000 x 3 x 0.135 = 405

* Case of different classes of plant working on same fill Compaction energy applied by a machine is taken as Ci = [Q/S]table / [Q/S]i in which [Q/S]table is the Q/S value prescribed for machine i for the soil to attain a satisfactory degree of compaction [Q/S]i is the Q/S value obtained by machine i in the time considered. The requirement for obtaining the compaction with n compacting plants is: i=n

i=1

C(i

42

1)

Q/S e V N Q/L 0

4

400

0.045

N

Q/L

Q/S

Code 3

43

225

N

Q/L

Code 2

175

Q/L

(m) (m) (km/h) (m3/h.m) Machine type unsuitable

6

N

250

6

5.0

0.30

0.050

475

5

5.0

0.45

0.095

900

4

5.0

0.60 (1)

0.180

P3

0

0

110

5

2.0

0.25

0.055

V1

50

8

2.0

0.20

0.025

80

7

2.0

0.25

0.040

215

5

2.5

0.35

0.085

V2

165

5

2.5

0.30

80

8

2.0

0.30

130

7

2.0

0.40

315

4

2.5

0.50

0.040

0.065

500

3

4.0

0.30

0.125

V3

125

6

2.5

0.30

300

4

3.5

0.30

825

3

5.0

0.35 (1)

170

6

2.0

0.50

100

8

2.0

0.40

0.050

0.085

415

4

2.5

0.65 (1)

0.165

V4

195

5

3.0

0.30

400

3

4.0

515

4

2.5

0.80 (1)

200

6

2.0

0.60

130

7

2.0

0.45

0.065

0.30

0.100

1025

2

5.0

V5

0.205 0.40 (1)

(*) Required Dmax < 2/3rds compacted layer thickness (1) Check trafficability for machine (2) Provide for removing ruts when there is a risk of rain at close of working day (plane off top few centimetres or use another type of roller if it produces the desired result)

5.0

0.20

Code 1

0

V

e

0.035

325

6

5.0

0.35

0.065

600

4

5.0

0.45 (1)

0.120

P2

High compaction energy

Q/S

6

V

energy

5.0

e

Moderate compaction

0.25

5.0

V

energy

0.30

0.080

e

Q/S

P1

Compaction tables for use of materials in fill

Low compaction

Method

Machine

A1, C1A1 (*)

6.3.2 Compaction tables

0

0

110

5

2.0

0.25 (2)

0.055

VP1

50

8

2.0

0.20

0.025

80

7

2.0

0.25 (2)

0.040

255

4

3.0

0.30 (2)

0.085

VP2

100

6

2.0

0.30

0.050

215

4

2.5

0.30 (2)

0.085

660

2

4.0

0.30 (2)

0.165

VP3

165

5

2.5

0.30

0.065

350

3

3.5

0.30 (2)

0.100

1025

2

5.0

0.35 (2)

0.205

VP4

255

4

3.0

0.30

0.085

520

3

4.0

0.30 (2)

0.130

1325

2

5.0

0.40 (2)

0.265

VP5

0

320

5

8.0

0.20 (2)

0.040

560

4

8.0

0.25 (2)

0.070

SP1

280

8

8.0

0.25

0.035

560

5

8.0

0.30 (2)

0.070

800

4

8.0

0.40 (2)

0.100

SP2

0

0

0

PQ3

0

0

65

3

1.0

0.20 (1)

0.065

PQ4


44

Q/S e V N Q/L 0

150

Q/L


7

N

200

8

5.0

0.30

0.040

350

5

5.0

0.35

0.070

600

4

5.0

0.45

0.120

P3

0

0

80

5

2.0

0.20

0.040

V1

0

70

6

2.0

0.20

0.035

120

5

2.0

0.30

0.060

V2

100

6

2.0

0.30

225

4

2.5

0.35

70

8

2.0

0.25

0.035

0.050

270

4

3.0

0.30

0.090

V3

165

5

2.5

0.30

480

3

4.0

0.30

90

8

2.0

0.35

0.045

130

7

2.0

0.40

0.065

300

4

2.5

0.45

0.120

V4

140

6

2.5

0.30

240

4

3.0

365

5

2.5

0.60

0.145

V5

110

8

2.0

0.40

0.055

160

6

2.0

0.45

0.080

0.30

725

3

5.0

0.30

(*) Required Dmax < 2/3rds compacted layer thickness (1) Check trafficability for machine (2) Provide for removing ruts when there is a risk of rain at close of working day (plane off top few centimetres or use another type of roller if it produces the desired result)

5.0

0.20

Code 1

0

V

e

0.030

250

5

5.0

0.25

0.050

400

5

5.0

0.35

0.080

P2


Q/S

7

150

N

Q/L

Code 2

5.0

V

energy

0.20

e

0.030

Q/S

Moderate compaction

5

250

Code 3

5.0

N

V

energy

0.25

Q/L

e

0.050

P1


Q/S

Low compaction

Method

Machine

A2, C1 A2 (*)

0

0

80

5

2.0

0.20 (2)

0.040

VP1

0

70

6

2.0

0.20 (2)

0.035

120

5

2.0

0.30 (2)

0.060

VP2

90

6

2.0

0.25

0.045

130

5

2.0

0.30 (2)

0.065

360

3

3.0

0.30 (2)

0.120

VP3

110

6

2.0

0.30

0.055

200

4

2.5

0.30 (2)

0.080

580

3

4.0

0.30 (2)

0.145

VP4

175

5

2.5

0.30

0.070

315

3

3.0

0.30 (2)

0.105

950

2

5.0

0.30 (2)

0.190

VP5

0

280

6

8.0

0.20 (2)

0.035

520

4

8.0

0.25 (2)

0.065

SP1

240

7

8,0

0.20

0.030

480

5

8.0

0.30 (2)

0.060

800

4

8.0

0.40 (2)

0.100

SP2

0

0

0

PQ3

0

0

0

PQ4


45

Q/S e V N Q/L 0

150

Q/L


7

0

0

0

V1

0

0

80

5

2.0

0.20

0.040

V2

0

0.035

0

70

6

2.0

0.20

110

5

2.0

0.25

0.055

V3

140

5

2.0

0.35

4 255

V5

70

8

2.0

0.25

0.035

110

2.0

0.30

0.055

170

6

2.0

0.45

0.085

3.0

0.30

(2) Provide for removing ruts when there is a risk of rain at close of working day (plane off top few centimetres or use another type of roller if it produces the desired result)

60

7

2.0

0.20

0.030

90

6

2.0

0.25

0.045

175

5

2.5

V4 0.070 0.30

(*) Required Dmax < 2/3rds compacted layer thickness

5.0

0.20

N

0

Code 1

0

V

e

0.030

250

6

5.0

0.30

0.050

300

6

5.0

0.35

0.060

P3


Q/S

7

150

N

Q/L

5.0

0.20

Code 2

0

V

e

0.030

200

7

5.0

0.25

0.040

P2

energy

compaction

Moderate

Q/S

10

100

N

Q/L

Code 3

5.0

0.20

0.020

V

e

Q/S

P1


energy

compaction

Low

Method

Machine

A3, C1A3 (*)

0

0

0

VP1

0

0

80

5

2.0

(2)

0.20

0.040

VP2

0

90

5

2.0

0.20

0.045

140

4

2.0

(2)

0.25

0.070

VP3

70

6

2.0

0.20

0.035

110

5

2.0

0.25

0.055

215

4

2.5

(2)

0.30

0.085

VP4

90

6

2.0

0.25

0.045

140

5

2.0

0.30

0.070

330

4

3.0

(2)

0.30

0.110

VP5

560

5

8.0

(2)

0.35

0.070

SP2

0

200

8

8.0

0.20

200

8

8.0

0.20

0.025

360

6

8.0

0.25

0.025 0.045

320

7

8.0

(2)

0.25

0.040

SP1

0

0

0

PQ3

0

0

0

PQ4


46

Q/S (m) e (m) V (km/h) N Q/L (m3/h.m) 0 Machine type unsuitable

6

275

N

Q/L

Code 2

5.0

0.30

0.055

P1

V

e

Q/S

6

600

7

110

6 170

3 675

6 270

3 900

360

7

2.0

(1)

1.10

575

6

5.0

0.60

0.115

P3

100

6

2.0

0.30

0.050

V1

160

7

2.0

0.50

0.080

V2

600

3

5.0

0.30

240

7

2.0

0.75

0.120

V3

825

3

5.0

0.40

(*) Required Dmax < 2/3rds compacted layer thickness (1) Check roller trafficability

400

5

5.0

0.40

0.080

P2

330

7

2.0

1.00

0.165

V4


energy

compaction

Moderate

Method

Machine

B3, D2, C1B3 (*) C1D2 (*)

5

450

2.0

6

5.0

V4 0.180 0.45

300

2.0

0.80

N

2.0

0.30

0.135

Q/L

5.0

0.50

0.085

V3

Code 2

5.0

0.35

0.055

V2

5.0

5.0

0.65

0.120

V1

V

0.45

0.090

P3

energy

0.35

0.060

P2

(1)

e

Q/S

P1


compaction

Moderate

Method

Machine

B1, D1, C1B1(*), C1D1 (*)

1000

3

5.0

0.50

V5

400

6

2.0

1.20

450

6

2.0

(1)

1.35

0.200

1125

3

5.0

(1)

0.55

0.225

V5

0

VP1

0

VP1

0

VP2

0

VP2

0

VP3

0

VP3

0

VP4

0

VP4

0

VP5

0

VP5

0

SP1

0

SP1

0

SP2

0

SP2

65

6

1.0

0.40

0.65

PQ3

75

6

1.0

0.45

0.075

PQ3

90

6

1,0

0.55

0.090

PQ4

100

6

1.0

0.60

0.100

PQ4


47

Q/S e V N Q/L 0

150

Q/L


7

N

Code 1

5.0

0.20

V

e

0.030

Q/S

energy

compaction

High

5

300

N

Code 2

5.0

0.25

Q/L

V

e

0.060

Q/S

energy

compaction

Moderate

3

500

N

Code 3

5.0

0.30

0.100

P1

350

6

5.0

0.40

0.070

650

4

5.0

0.50

0.130

1250

3

5.0

0.65

0.250

P3

50

8

2.0

0.20

0.025

90

6

2.0

0.25

0.045

215

5

2.5

0.35

0.085

V1

70

9

2.0

0.30

0.035

140

6

2.0

0.40

0.070

340

5

2.5

0.55

0.135

V2

165

6

3.0

0.30

475

3

4.5

0.30

110

9

2.0

0.45

0.055

210

7

2.0

0.65

515

5

2.5

0.85

0.105

1025

2

5.0

0.40

0.205

V3

300

4

4.0

0.30

700

3

5.0

0.35

1375

2

5.0

0.55


225

6

5.0

0.25

0.045

450

4

5.0

0.35

0.090

750

3

5.0

0.45

0.150

P2

150

8

2.0

0.55

0.075

280

7

2.0

0.85

0.140

690

4

2.5

1.10

0.275

V4

430

4

4.5

0.30

875

3

5.0

0.40

190

8

2.0

0.70

0.095

350

6

2.0

1.05

850

4

2.5

1.35

0.340

V5

0.175

1700

3

5.0

0.70


Q/L

V

e

Q/S

energy

compaction

Low

Method

Machine

B2, B4, C1B2 (*), C1B4 (*)

0

0

0

VP1

0

0

0

VP2

0

0

0

VP3

0

0

0

VP4

0

0

0

VP5

0

0

0

SP1

0

0

0

SP2

200

2

1.0

0.40

0.200

PQ4

20

10

1.0

0.20

0.020

50

5

1.0

0.25

50

6

1.0

0.30

0.050

90

4

1.0

0.35

0.050 0.090

150

2

1.0

0.30

0.150

PQ3


Q/S e V N Q/L 0

Moderate

48

300

5

5.0

0.30

0.060

600

4

5.0

0.45

0.120

1000

3

5.0

0.60

0.200

P3

0

60

7

2.0

0.20

0.030

120

5

2.0

0.30

0.060

V1

60

7

2.0

0.20

0.030

100

6

2.0

0.30

0.050

240

5

2.5

0.40

0.095

V2

225

4

3.0

80

8

2.0

0.30

150

6

2.0

0.45

365

5

2.5

0.60

0.040

0.075 0.30

725

3

5.0

0.30

0.145

V3

140

7

2.5

0.35

400

3

4.0

110

8

2.0

0.40

0.055

200

6

2.0

0.60

490

5

2.5

0.80

0.195

V4

0.100 0.30

975

3

5.0

0.40


200

Q/L


5

N

5.0

0.20

Code 1

0

V

e

0.040

400

5

5.0

0.35

0.080

650

4

5.0

0.45

0.130

P2

energy

compaction

High

Q/S

5

250

N

Q/L

Code 2

5.0

0.25

V

e

0.050

Q/S

energy

compaction

4

450

N

Code 3

5.0

0.30

0.090

P1


Q/L

V

e

Q/S

energy

compaction

Low

Method

Machine

B5, C1B5 (*)

230

5

3.5

0.30

600

3

5.0

0.30

590

4

2.5

0.95

130

8

2.0

0.50

0.065

240

7

2.0

0.75

0.120

1175

2

5.0

0.45

0.235

V5

0

0

0

VP1

0

0

0

VP2

0

0

0

VP3

0

0

0

VP4

0

0

0

VP5

0

0

0

SP1

0

0

0

SP2

0

0

65

3

1.0

0.20

0.065

PQ3

0

50

4

1.0

0.20

0.050

100

3

1.0

0.30

0.100

PQ4


49

Q/S e V N Q/L 0

4

200

7

5.0

0.25

0.040

375

5

5.0

0.35

0.075

600

0

0

90

6

2.0

50

8

2.0

0.20

0.025

80

7

2.0

0.25

0.040

190

4

2.5

0

150

5

2.5

120

6

2.0

70

8

2.0

0.25

0.035

0.30

0.35

275

5

2.5

0.45

0.060

385

3

3.5

0.30

0.110

115

7

2.5

0.30

160

7

2.0

0.50

90

8

2.0

0.35

0.045

240

4

3.0

365

5

2.5

0.60

0.080 0.30

725

3

5.0

0.30

0.145

V4

165

6

3.0

0.30

190

7

2.0

0.60

450

4

2.5

0.70

110

8

2.0

0.40

0.055

380

4

4.0

0.30

0.095

900

2

5.0

V5 0.180 0.35

(*) Required Dmax < 2/3rds compacted layer thickness (2) Provide for removing ruts when there is a risk of rain at close of working day (plane off top few centimetres or use another type of roller f it produces the desired result)

150

Q/L


7

N

5.0

0.20

Code 1

0

0.030

250

5

5.0

0.25

0.050

V

e

4

375

energy

compaction

High

Q/S

7

150

N

Q/L

Code 2

5.0

0.20

V

e

0.030

Q/S

energy

compaction

Moderate

5

225

N

Q/L

5.0

0.30

0.075

V3

0.25

0.045

VP1

0

0

90

6

Code 3

5.0

0.25

0.045

V2

2.0

5.0

0.45

0.120

V1

V

0.30

0.075

P3

energy

0.20

0.045

P2

(2)

e

Q/S

P1


compaction

Low

Method

Machine

B6, C1B6 (*) VP3

50

8

2.0

0.20

0.025

80

7

2.0

(2)

0.25

0.040

190

4

2.5

(2)

0.30

90

6

2.0

0.25

0.045

200

4

2.5

(2)

0.30

0.080

510

3

3.5

(2)

0.30

0.075 0.145

VP2

140

6

2.5

0.30

0.055

285

4

3.0

(2)

0.30

0.095

900

2

5.0

(2)

0.30

0.180

VP4

210

5

3.0

0.30

0.070

500

3

4.0

(2)

0.30

0.125

1175

2

5.0

(2)

0.35

0.235

VP5

0

400

4

8.0

(2)

0.20

0.050

640

4

8.0

(2)

0.25

0.080

SP1

280

6

8.0

0.20

0.035

600

4

8.0

(2)

0.30

0.075

960

4

8.0

(2)

0.40

0.120

SP2

0

0

50

4

1.0

0.20

0.050

PQ3

0

0

85

3

1.0

0.25

0.085

PQ4


50

4

250

6

5.0

0.30

0.050

450

5

5.0

0.40

0.090

750

0

0

100

5

2.0

50

8

2.0

0.20

0.025

80

7

2.0

0.25

0.040

200

4

2.5

0.060

300

5

2.5

0.50

80

8

2.0

0.30

120

6

2.0

0.35

0.040

150

5

2.5

0.30

480

3

4.0

0.30

0.120

0.080

125

6

2.5

0.30

160

7

2.0

0.50

400

5

2.5

0.65

100

8

2.0

0.40

0.050

240

4

3.0

0.30

800

2

5.0

0.30

0.160

V4

V5

195

5

3.0

0.30

0.065

400

3

4.0

130

7

2.0

0.45

200

6

2.0

0.60

0.100

475

4

2.5

0.75

0.190

0.30

950

3

5.0

0.40

(*) Required Dmax < 2/3rds compacted layer thickness (**)Only C2(A1) soils can be compacted with tamping rollers (2) Provide for removing ruts when there is a risk of rain at close of working day (plane off top few centimetres or use another type of roller if it produces the desired result)

150

Q/L

Q/S (m) e (m) V (km/h) N Q/L (m3/h.m) 0 Machine type unsuitable

7

N

5.0

0.20

Code 1

0

V

e

0.030

300

5

5.0

0.30

energy

compaction

High

Q/S

5

200

N

Q/L

Code 2

5.0

0.20

V

e

energy

compaction

Moderate

0.040 0.060

Q/S

4

500

4

350

N

Q/L

5.0

0.30

0.080

V3

0.25

5

0

0

100

50

8

2.0

0.20

0.025

80

7

2.0

(2)

0.25

0.040

200

4

2.5

(2)

0.30

0.080

(**)

(**) 0.050

VP2

VP1

Code 3

5.0

0.25

0.050

V2

2.0

5.0

0.50

0.150

V1

V

0.35

0.100

P3

energy

0.25

0.070

P2

(2)

e

Q/S

P1


compaction

Low

Method

Machine

C2A1 (*), C2 B2 (*), C2 B4 (*), C2B5 (*)

100

6

2.0

0.30

0.050

200

4

2.5

(2)

0.30

0.080

640

2

4.0

(2)

0.30

0.160

(**)

VP3

165

5

2.5

0.30

0.065

300

3

3.0

(2)

0.30

0.100

950

2

5.0

(2)

0.30

0.190

(**)

VP4

255

4

3.0

0.30

0.085

520

3

4.0

(2)

0.30

0.130

1225

2

5.0

(2)

0.40

0.245

(**)

VP5

0

0

560

4

8.0

(2)

0.25

0.070

(**)

SP1

0

400

5

8.0

(2)

0.25

0.050

800

4

8.0

(2)

0.40

0.100

(**)

SP2

0

0

0

PQ3

0

40

5

1.0

0.20

65

4

1.0

0.25

0.065

PQ4


51

Q/S e V N Q/L 0

4

200

7

5.0

0.25

0.040

350

5

5.0

0.30

0.070

500

0

0

70

6

2.0

50

8

2.0

0.20

0.025

70

6

2.0

0.20

0.035

110

5

2.0

160

5

2.0

0.40

70

8

2.0

0.25

0.035

110

6

2.0

0.30

0.055

200

4

2.5

0.30

0.080

210

2.5

0.30

115

7

140

6

2.0

0.40

90

8

2.0

0.35

0.045

210

5

3.0

0.30

6

2.0

0.55

0.070

370

3

3.5

0.30

0.105

V4

3.5

0.30

0.30

165

6

3.0

170

6

2.0

0.50

110

8

2.0

0.40

0.055

300

4

260

5

2.0

0.65

0.085

585

3

4.5

V5 0.130 0.30

(*) Required Dmax < 2/3rds compacted layer thickness (2) Provide for removing ruts when there is a risk of rain at close of working day (plane off top few centimetres or use another type of roller if it produces the desired result)

125

Q/L


8

N

5.0

0.20

Code 1

0

0.025

225

6

5.0

0.25

0.045

V

e

4

375

energy

compaction

High

Q/S

7

150

N

Q/L

Code 2

5.0

0.20

V

e

0.030

Q/S

energy

compaction

Moderate

4

250

N

Q/L

5.0

0.25

0.055

V3

0.20

0.035

VP1

0

0

70

6

Code 3

5.0

0.20

0.035

V2

2.0

5.0

0.40

0.100

V1

V

0.30

0.075

P3

energy

0.20

0.050

P2

(2)

e

Q/S

P1

compaction

Low

Method

Machine

C2A2 (*), C2 A3 (*), C2 B6 (*) Compaction tables for use of materials in fill

50

8

2.0

0.20

0.025

70

6

2.0

(2)

0.20

0.035

110

5

2.0

(2)

0.25

0.055

VP2

90

6

2.0

0.25

0.045

140

5

2.0

(2)

0.30

0.070

265

3

2.5

(2)

0.30

0.105

VP3

140

6

2.5

0.30

0.055

255

4

3.0

(2)

0.30

0.085

455

3

3.5

(2)

0.30

0.130

VP4

210

5

3.0

0.30

0.070

385

3

3.5

(2)

0.30

0.110

765

2

4.5

(2)

0.30

0.170

VP5

0

0

400

4

8.0

(2)

0.20

0.050

SP1

0

360

6

8.0

(2)

0.25

0.045

720

4

8.0

(2)

0.35

0.090

SP2

0

0

0

PQ3

0

35

6

1.0

0.20

0.035

50

5

1.0

0.25

0.050

PQ4


52

Q/S e V N Q/L 0

0


500

5

5.0

0.50

0.100

P3

70

6

2.0

0.20

0.035

V1

110

7

2.0

0.35

0.055

V2

300

4

3.5

0.30

170

6

2.0

0.50

0.085

V3

250

7

5.0

0.35

0.050

425

5

5.0

0.40

0.085

P3

0

0

V1

60

9

2.0

0.25

0.030

100

5

2.0

0.25

0.050

V2

115

7

2.5

0.30

150

6

2.0

0.40

90

8

2.0

0.35

0.045

190

4

2.5

0.30

0.075

V3

180

5

3.0

120

8

2.0

0.45

200

5

2.0

0.50

230

7

2.0

V5

3

4.0

0.30

0.070

480

280

280

7

2.0

0.85

140

9

2.0

0.60

240

5

2.0

0.60

0.120

4.0

5

V5 0.140

0.30

700

3

5.0

0.70 0.35

0.100

V4

0.115

V4

0.060 0.30

350

3

3.5

0.30

520

3

4.5

0.30


9

150

N

Q/L

Code 2

5.0

0.25

V

e

0.030

Q/S

energy

compaction

High

6

250

5.0

0.30

0.050

P2

N

Code 3

0

P1

Q/L

V

energy

e

Q/S

Machine

compaction

Moderate

Method

350

5

5.0

0.35

0.070

P2


225

Q/L

R1 (*)

6

N

Code 3

5.0

0.25

0.045

V

e

Q/S

P1


energy

compaction

Moderate

Method

Machine

C2D1 (*), C2 D2 (*), C2 B1 (*), C2 B3

0

0

VP1

0

VP1

VP3

0

VP3

60

9

2.0

0.25

0.030

100

5

2.0

0.25

150

5

2.5

0.30

0.060

250

3

2.5

0.30

0.050 0.100

VP2

0

VP2

210

5

3.0

0.30

0.070

420

3

3.5

0.30

0.120

VP4

0

VP4

360

4

4.0

0.30

0.090

620

2

4.0

0.30

0.155

VP5

0

VP5

240

9

8.0

0.25

0.030

400

6

8.0

0.30

0.050

SP1

0

SP1

400

6

8.0

0.30

0.050

640

5

8.0

0.35

0.080

SP2

0

SP2

PQ4

65

6

1.0

0.40

0.065

PQ4

0

40

6

1.0

0.25

25

8

1.0

0.20

0.025

50

6

1.0

0.30

0.040 0.050

PQ3

50

6

1.0

0.30

0.050

PQ3


53

Q/S e V N Q/L 0


70

6

2.0

0.20

0.035

V1

120

6

2.0

0.35

0.060

V2

315

4

3.5

0.30

180

7

2.0

0.55

0.090

V3

200

8

5.0

0.30

0.040

275

7

5.0

0.35

0.055

P3

0

0

V1

40

10

2.0

0.20

0.020

70

6

2.0

0.20

0.035

V2

0.035

70

8

2.0

0.25

100

6

2.0

0.30

0.050

V3

115

7

2.5

130

7

2.0

0.40

90

8

2.0

0.35

0.045 0.30

165

5

2.5

0.30

V4

230

7

2.0

0.70

0.065

520

3

4.5

0.30

0.115

V4

165

6

3.0

110

8

2.0

0.40

160

7

2.0

0.50

0.055 0.30

240

4

3.0

0.30

V5

290

6

2.0

0.85

0.080

725

3

5.0

V5

0.145 0.35

(*) Required Dmax < 2/3rds compacted layer thickness (2) Provide for removing ruts when there is a risk of rain at close of working day (plane off top few centimetres or use another type of roller if it produces the desired result)

8

125

N

Q/L

5.0

0.20

Code 2

0

V

e

0.025

175

8

5.0

0.25

0.035

P2

energy

compaction

Q/S

10

100

N

Q/L

Code 3

5.0

0.20

0.020

V

e

Q/S

P1

energy

High

400

5

5.0

0.40

0.080

P3



Machine

compaction

Moderate

Method

R3 (*)

6

250

N

Q/L

5.0

0.30

Code 3

0

0.050

P2

V

e

Q/S

P1

energy

compaction

Moderate

Method

Machine

R21 (*), R41 (*), R61 (*),

0

0

VP1

0

VP1

40

10

2.0

0.20

0.020

70

6

2.0

(2)

0.20

0.035

VP2

0

VP2

90

6

2.0

0.25

0.045

130

5

2.0

(2)

0.30

0.065

VP3

0

VP3

140

6

2.5

0.30

0.055

200

4

2.5

(2)

0.30

0.080

VP4

0

VP4

210

5

3.0

0.30

0.070

315

3

3.0

(2)

0.30

0.105

VP5

0

VP5

200

8

8.0

0.20

0.025

360

6

8.0

(2)

0.25

0.045

SP1

0

SP1

320

8

8.0

0.30

0.040

560

5

8.0

(2)

0.35

0.070

SP2

SP2

0

0

PQ3

50

6

1.0

0.30

0.050

PQ3

0

0

PQ4

65

6

1.0

0.40

0.065

PQ4



6.4 Continuous monitoring of compaction Monitoring results on the completed structure or each constituent layer by measuring the inplace bulk unit weight usually involves many problems as seen in section 6-1. Continuous compaction monitoring has the merit of referring directly to the compaction “rules” which, if they have a sound scientific foundation backed up by experience (see tables in section 6-3-2), ensure the quality of construction.

6.4.1 Specifications Specifications on “continuous” compaction monitoring consist of prescribing rules for each combination of soil class and compaction machine in given weather conditions liable to occur during performance of the work. This covers: - maximum layer thickness e of soil layers after compaction, which must be compatible with efficient operation of the roller used, - intensity of compaction to be applied, expressed by the Q/S ratio in which Q is the volume of soil placed (measured after compaction) and S is the area covered by the machine to compact volume Q, - roller operating conditions: maximum forward speed of vibratory machines, minimum speed for spreading machines, ballast, vibrational frequency and eccentric moment for vibratory machines, tyre pressure for pneumatic tyred rollers, - fitting machines with direct reading and recording instruments for distance travelled by the machine, forward speed and (for vibrating rollers) vibrational frequency and eccentric moment, - site organisation: contractor to submit a schedule for operating haulage, spreading and compaction each day or less systematically, whenever he makes changes, - in some cases, contractor to submit details of volume of material placed during the sequence chosen for conducting the compaction intensity control Q/S (usually a day or half-day).

Tachograph equiped roller recording passed distance, speed and vibration of the plant during compacting operation.

In most cases, prescribed values for e and Q/S are taken from the tables in 6-3-2 above showing the relevant values for different soil classes and compaction machines. Failing that, the contract might state the values which can be set on the basis of trial embankments built at the start of the job, but this approach is less satisfactory, because compaction requirements are not specified until after the contract has been signed.

54


As a general rule, the tolerances tabulated below should be used for the e and Q/S values. Tolerances Compaction required

Low Intense & moderate

e

Q/S

+ 15% e measured = e prescribed - 15% e measured < e prescribed

+ 20% Q/S measured = Q/S prescribed - 20% Q/S measured < Q/S prescribed

6.4.2 Monitoring operations The “continuous” compaction monitoring procedure covers: - materials (identification of soil types and states as described in section 5) and weather conditions during placement, - compaction plant used (verification of machine class according to the classification described in section 6-2); - compacted layer thickness (verification of compliance with stipulated maximum thicknesses as described in section 6-3); - compacted soil volumes (per sequence during which soil conditions, weather and compaction details are considered uniform) to calculate actual Q/S for comparison with prescribed Q/S, - areas covered by the compaction machines to find the covered area S and calculate the actual Q/S obtained, - roller operating parameters (forward speed, frequency, eccentric moment as described in section 5-2), - coverage pattern (verification of uniformity of compaction over the cross section, etc.). Measurement of layer thickness is simple but must be done with care using appropriate apparatus: a level for precision measurements (on trial embankments), or more routinely a graduated staff, thickness gauge or tape measure. Estimation by eye is to be avoided as far as possible because it is inaccurate, sometimes by as much as the prescribed tolerances. It is frequently best to make the measurements when the soil is being spread (while estimating the effect of compaction) because obviously, it is easier at this time to make any necessary corrections. The volume of compacted material Q can be measured in various ways: - directly by a topographic survey of the embankment, which is clearly the most accurate method but which is difficult to carry out. It can beneficially be used occasionally to cross-check and calibrate the following indirect methods, - indirectly by topographic survey of the extraction area or by counting the haulage plant and estimating individual loads. In both cases, the figures must be multiplied by a factor to allow for bulking.

55


As a general guide, this factor may have one of the undermentioned values: Rocky Materials Estimation Method Survey of extraction area Estimated haulage plant loads

extracted with explosives 1.3 0.85

extracted by ripper 1.15 0.75

Soils clay 1 0.7

non clay 1 0.9

Estimating material volumes from haulage plant loads might appear to be the most convenient method but it must be realised that it is fairly inaccurate and involves a continuous watch on plant rotations, a difficulty requiring careful consideration when drafting the contract if it is planned for the contractor to bear responsibility for this item. The area covered by the compaction plant is measured by multiplying the compaction width by the distance travelled. Travel distance can be conveniently and accurately determined with recording tachographs of the type routinely used in the road haulage industry (although they must be suitably modified and calibrated to allow them to be fitted to rollers, but practically all modern rollers can be so equipped). The client must check the instrument is fitted to every roller and carefully check that it is working properly and correctly calibrated. The frequency of Q and S measurements should, strictly speaking, be dependent on the variability in site conditions. In the most usual situations, in which conditions do not vary over the whole working day, daily measurements can be considered satisfactory. More frequent measurements, every half-day or even every hour, may have to be considered for special operations (placing fill against culvert, bridge, etc.) or when conditions undergo a sudden significant change. Regarding monitoring of roller operating details: ballast, forward speed, vibrational frequency, spot checks can be made (for ballast mainly) but the only true guarantee of compliance with the specifications are recordings from the tachographs already mentioned. Such records will show up any flaws in the performance of the works: excess vibratory roller speed, vibration interruptions, mismatch between material deliveries and compaction times, etc., flaws which could not easily be detected by any other method. Electronic recorders with computer processing of data are being developed.

56

Use of soils and rocky materials in embankment construction • Particular case of use of arid soils

7. Particular case of use of arid soils 7.1 Advantages of, and basis for dry compaction In some dry and arid climates, adding water to achieve the moisture content qualifying the material as “dry” for compaction purposes (q4 compaction) may be relatively expensive (involving drilling, pumping, haulage, spreading, perhaps blending, site organisation) and in some cases consume large amounts of a rare resource. Experimental research conducted in the early eighties through controlled trials at CER Rouen and construction sites in Algeria and Niger led to recommendations for compacting soils with near-zero moisture content9.

7.2 Definition of arid soils - application scope of the method 7.2.1 Nature of concerned soils The soils which have been successfully experimented in this way are the following (according to classification of § 4-2 before): The proposed method applies only to the above soil classes. Soils

GTR classification

Fine soils Fines - rich sand and gravel soils Fines - poor sand soils Fines - poor gravel soils Coarse soils

A1, A2 B5, B6 D1, B1, B2 D2, B3, B4 C1A1, C1A2, C1B5, C1B6, C1D1, C1B1, C1B2, C1D2, C1B3, C1B4 C2A1, C2A2, C2B5, C2B6, C2D1, C2B1, C2B2, C2D2, C2B3, C2B4

7.2.2 Definition of moisture state “arid” When a Proctor test is carried out on samples which have an initial moisture content close to zero, a minimum density appears at a

moisture content Wc known as critical moisture content, as shown on following figure. Proctor curves obtained with a range of moisture contents close to zero.

Soils in an “arid” state.

The arid state corresponds to a moisture content between zero and Wc. From this graph, we can conclude that the lower the moisture content in this range, the more 9. ISTED - Institut des Sciences et des Techniques de l’Equipement et de l’environnement pour le Développement : “Compactage à faible teneur en eau des sols et matériaux de terrassements et de chaussées” (Juin 1987).

57


compaction is efficient. This is often true, but sometimes the soil becomes too dusty and its poor Soils class A1 a A2 a B1 a B2 a B3 a B4 a B5 a B6 a (C1-Xi)a

Range of moisture contents corresponding to arid state 310 à 7 410 à 8 <3 <4 <3à4 <4 <3à4 <3à5 Defined by the state of Xi

trafficability decreases compaction efficiency. The ranges of arid state defined below, take these facts into account.

7.2.3 “Arid” state classes of soils 7.2.4 Acceptable embankment height Arid state soils which are dry-compacted according the following tables can be used in embankments the height of which must not exceed 3 metres. Necessary precautions must be taken to protect them from erosion, particularly by ravining.

7.3 Compaction tables The compaction conditions given in the following tables for smooth vibrating drum rollers (Vi) normally produce a main body fill of q4 standard. The tables are similar to those given in section 5 for wet soils (low compaction), normal soils (moderate compaction) or dry soils (intense compaction); they are used in the same way. It is however useful to understand and allow for certain particularities of “dry compaction” when using this method. These are briefly described in the following paragraphs.

7.4 Particularities of dry compaction • Risks of insufficient or zero compaction are very difficult to detect by eye during the work (plant trafficability is not closely dependent on compaction, the surface condition of the layer being compacted undergoes little change with the number of passes). Correct compliance with the compaction pattern calls for vigilance on the part of the roller operator. • “Standard” equipment for measuring unit weight from the surface (gammadensimeter, membrane densimeter or sand method) yields no information on compaction because the top of the layer is not (or very lightly) compacted, it is compacted when the subsequent layer is placed. • Plate bearing test (EV2/EV1) or other means of determining the deformation modulus by applying load to the top of the layer are entirely inappropriate. • A strict compliance with the compaction method given in the compaction tables is therefore the most important guarantee of the quality of construction: continuous monitoring is essential (see section 6-4). The following points demand special attention: - The thickness shown for the layer is the maximum permitted value (depending on plant used, the specifications may refer to the value in the table +0 to x cm). - The forward speed shown is also the maximum value. - Vibratory rollers must be operated at maximum amplitude of vibration.

10. For moisture contents less than these values, it is first necessary to verify that trafficability for compacting machines are compatible with an efficient compaction.

58


Post facto verification of compaction quality can be carried out with a double gamma probe or dynamic penetrometer.

SOILS

B1 D1 C1B1(*) C1D1(*)

SOILS

B3 D2 C1B3(*) C1D2(*)

SOILS

C2D1(*) C2D2(*) C2B1(*) C2B3(*)

CLASS OF VIBRATORY ROLLER V1 V2 V3 V4 V5



Q/S

e

0.050 0.080 0.130 0.170 0.215

0.30 0.40 0.55 0.65 0.75

Q/S

e

0.045 0.075 0.110 0.140 0.180

0.25 0.35 0.45 0.55 0.65

Q/S

e

0.055 0.085 0.115 0.140

0.30 0.40 0.50 0.55

V

N

2.0 2.0 2.5 3.0 3.5

6 5 4 4 4

V

100 160 340 490 650

N

2.0 2.0 2.5 3.0 3.5

6 5 4 4 4

V

N

2.0 2.5 3.0 3.0

6 5 5 4

59

Q/L

Q/L

REMARKS

When using combinations of widely differing compaction plant classes use the heavier items first - they are good for dry compaction in terms of final quality but involve trafficability problems.

REMARKS

80 140 280 410 560

Q/L

120 200 300 410

REMARKS

Class V1 rollers can be used to improve the top of the layer


SOILS

B2 B4 C1B2(*) C1B4(*)


Q/S

e

0.030 0.045 0.060 0.075

0.25 0.30 0.35 0.40

V

N

2.0 2.5 3.0 3.0

8 7 6 6

Q/L

60 110 175 200

REMARKS

Class V1 rollers can be used to improve the top of the layer

7.5 “Dry compaction” trial embankments SOILS

B5 C1B5(*)

SOILS

A1 C1A1(*) B6 C1B6(*) C2A1(*) C2B2(*) C2B4(*) C2B5(*)


CLASS OF VIBRATORY ROLLER

Q/S

e

0.020 0.030 0.040 0.055

0.20 0.25 0.30 0.35

Q/S

e

V

2 2 2.5 2.5

N

Q/L

10 9 8 7

40 55 90 125

N

Q/L

V

REMARKS

Surface cohesion (for the top part of the fill in particular) can beneficially be improved by sprinkling (7-10litres/m2) and compacting by pneumatic tyred roller P2

REMARKS

V1 V2

0.015 0.15

2

10

30

V3 V4 V5

0.025 0.20 0.038 0.30 0.048 0.35

2 2 2.5

8 8 8

50 75 110

- as above -

To set conditions for use of soils not included in the tables (rock and materials displaying special SOILS

A2 C1A2(*) C2A2(*) C2B6(*)


Q/S

e

0.018 0.20 0.030 0.25 0.040 0.30

V

2.0 2.0 2.0

N

Q/L

12 9 8

30 55 75

REMARKS

- as above -

behaviour), the above measuring systems must always be used in experimental on construction jobs or trials. Attention is drawn to the fact that “conventional” trials (compaction in a single layer) are not usually adequate for drawing conclusions. It is strongly recommended to compact at least two layers, one above the other, to assess the quality of the 15-18cm thickness on either side of the interface; if a penetrometer is used, the total thickness should be about one metre.

60

Document published by the LCPC under the number 51123111 Layout and production: Poly Print Agence / Baton Rouge Printing: Bialec Copyright: 3rd quarter 2003 - N° 59148

This Manual is an excerpt from the Technical Guidelines on Embankment and Capping Layers Construction (abbreviated to its French acronym GTR) issued September 1992 in France by LCPC and SETRA. However, this excerpt from the Guidelines concerns only the part dealing with the classification of natural soils (known as "GIR classification" according to the french norma NF 11300) and their use as fill for embankments (excluding all reference to organic topsoils and industrial by-products and requirements for their use in capping layers construction).

Réf : GTRA Prix : 23 € HT

Practical Manual for the Use of Soils and Rocky Materials in Embankment Construction

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