Chapter 6 Earthworks 4

Defence Engineering Engineering College

Department of Civil and combat

Engineering

CHAPTER 

Earthworks Quantities and Mass-Haul Diagram Introduction Earthwork for any road construction like (railway, landing and different types of highway) involves excavation and movement of o f a portion of the earth's surface from one location to another. Earthwork in a new position is an embankment being formed and created into a desired shape and physical grade formation or disposed of as spoil. Excavation of earth material is the removal of the layer of soil immediately under the topsoil and on top of rock for grade formation. Earth material is usually used to construct embankments and foundations and can be easily moved with scrapers or other types of earthmoving equipment for grade formation. Excavation of topsoil is the removal of the exposed layer of the earth's surface, including vegetation. ock excavation is the removal of a formation that cannot be excavated excav ated without drilling and blasting.

Earth Work Includes

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!learing

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"rubbing # clear off roots

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Excavation of drainage channels $ trenches

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Excavation of structures

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%orrows

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&aul $ verhaul

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"rading

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reparation of ide lopes

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econditioning of roadway ther operations for preparing the subgrade for highway or runway pavement construction

(&ighway Eng. **)

1

Highway I

(2016/17)

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Engineering

T!"es o# e$ca%ation Excavation may be classified by type of material +.

opsoil opsoil excavation

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Earth excavation

.

ock excavation

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0uck excavation

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2nclassified excavation

o soil soil excavat excavation ion

o soil soil excavat excavation ion o soil soil excava excavatio tion n

















Engineering

E$ca%ation ma! &e classi#ied &! the "ur"ose •

tripping

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oadway excavation

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3rainage or structure excavation

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%ridge excavation

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!hannel excavation

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4ooting excavation

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%orrow excavation

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3redge excavation

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2nderground Excavation

Estimation o# Earthwork Quantities'Establishing of the 5ertical 6lignment7 3etermination of the grade for each section depends on7 •

ype of highway.

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8ocation.

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ypes of material

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he grade may be chosen so as to balance the quantities of excavation (!2) $ embankment (4*88).

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!alculated.

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8ocated on the profile.

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!hecked to ensure adequate sight distance.

The (-ve) (-ve) sign indicates indicates an embankment

















Engineering

The (+ve) sign sign indicates indicates an ecavation ecavation

Cut and #ill *n earthmoving, cut and fill is the process of constructing a railway, road or canal whereby the amount of material from cuts roughly matches the amount of fill needed to make nearby embankments, embankmen ts, so minimi9ing the amount of construction labor.

Areas o# Cross-sections

















Engineering

4or irregular ground, there are different methods to calculate for example "raphical or plan meter method, !oordinate or other approximate method

E$am"le (or irregular ground )##sets #rom a straight line *a+ Regular s"aced o##sets ffsets ffsets at regularly regularly spaced intervals are shown in #ig , for this case, the area is found by the formula

;here b is the length of a common interval between offsets, offsets, and ho , h+ << << hn are the offsets offsets . he regular interval for the example of #ig , is a half station or 1= m

(ig ,

*&+ Irregular s"aced o##sets 4or irregularly irregularly curved boundaries boundaries like that in #ig  the spacing of offsets along the reference line varies spacing should be select so that the curved boundary is accurately defined when ad>acent offset points on it are connected by straight lines. 6 formula for calculating area for this case

















Engineering

E$am"le

!ompute the area of the tract shown in #ig .

(ig .6rea by offsets for a tract with a curved boundary

Calculating %olumes o# Earthwork o determining determining the earthwork volumes, there are several ways of calculating earthwork 1$ average end are method

-. yra yrami mid d form formul ulaa . ris rismo moid idal al form formul ulaa

,/ a%erag a%eragee en end d are are metho method d his method consists consists of averaging the cut and fill quantities quantities of ad>acent stations stations and multiplying multiplying by the distance between stations to produce cubic meters of excavation and embankment between the two



















Engineering

;here 6+ and 6- are the end areas 8 is is the distance between them. his method is entirely accurate only if the two end areas are equal. *f one end area is 9ero, the earthwork volume is a pyramid.

./ P!ra P!ram mid #orm #ormul ula a hus, as the area of one end of the earthwork volume approaches 9ero, the error in the volume calculated by the average end area method approaches 1= percent. 6 more accurate formula, known as















Defence Engineering Engineering College Engineering

Distri&ution Distri&ution o# the Earthworks Quantities


































Engineering

Earthmo%ing *n civil engineering, a cut or cutting is where soil or rock material from a hill or mountain is cut out to make way for a canal, road or railway line. *n cut and fill construction it keeps the route straight and:or flat, where the comparative cost or practicality of alternate solutions (such as diversion) is prohibitive. !ontrary to the general meaning of cutting, a cutting in construction is mechanically excavated or blasted out with carefully placed explosives. he cut may only be on one side of a slope slope,, or directly through the middle or top of a hill. "enerally, a cut is open at the top (otherwise it is a tunnel). 6 cut is (in a sense) the opposite of an embankment.

oad cutting

















Engineering

6ctivities involved in this process include7 • • • • • • •

excavating, loading, hauling, placing (dumping and spreading), compacting, grading, and 4inishing.

Efficient management of the earthmoving process requires7 • • •

accurate estimating of work quantities and >ob conditions, proper selection of equipment, and !ompetent >ob management.

./ E1u E1ui"m i"ment ent 2elect 2election ion •

he choice of equipment to be used on a construction pro>ect has a ma>or *nfluence on the efficiency and profitability of the construction operation.

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6lthough there are a number of factors that should be considered in selecting equipment for a pro>ect, the most important criterion criterion is the ability of the equipment to perform the required work.

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6mong those items of equipment capable of performing the >ob, the principal criterion for selection should be maximi9ing the profit or return on the investment produced by the equipment. e quipment.

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ther factors that should be considered when selecting equipment for a pro>ect include7 •

possible future use of the equipment,



















Engineering •

he basic relationship for estimating the production of all earthmoving equipment is7 rodu roduct ctio ion n @ 5o 5olume lume per per cyc cycle le A !yc !ycle less per per hour hour ( 

Eq.+ Eq.+))

he term Bvolume per cycleB should represent the average volume of material moved per equipment cycle.



hus the nominal capacity of the excavator or haul unit must be modified by an appropriate fill factor based on the type of material and equipment involved.

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he term Bcycles per hourB must include any appropriate efficiency factors, so that it represents the number of cycles actually achieved (or expected to be achieved) per hour.

he cost per unit of production calculated as follows7 !ost per unit of production @ Equipment cost per hour C Equipment production per hour. (Eq. -)

2oil Identi#ication and Classi#ication

















Engineering

,/ 2oil 2oil Cond Condit itio ions ns here are three principal conditions or states in which earthmoving material may exist or hree tates of 0aterial •

bank,

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loose, and

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!ompacted.

4ank' •

0aterial in its natural state before disturbance. ften referred to as Bin#placeB or Bin situ.B

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6 unit volume is identified as a bank cubic yard (%!D) or a bank cubic meter (%!0)

5oose' •

0aterial that has been excavated or loaded.

















Engineering

E$am"le , 4ind the swell of a soil that weighs ++ + + kg:m in its natural state and ++F kg:m after excavation. 2olution

well @(++:++F # +) A +==@/=GH hat is, + bank cubic meter of material will expand to +./ loose cubic meters after excavation.

0/ 2hrin rinkage age ;hen a soil is compacted, some of the air inside of the soil is forced out. 6s a result the soil occupies less volume than it does either in bank or loose conditions. his is the reverse of swell and called as shrinkage

2hrinkage 2hrinkage (actors hrinkage depends on7 •

materialIs characteristics

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method of placing

































Engineering

E$am"le "iven the end areas below, calculate the volumes of cut and fill between stations 1+?== and 1-?1=. *f the material shrinks +- percent, how much excess cut or fill is thereM



































Engineering

2olution

hrinkage @ (+# ++: -=NN) A +== @ -=G &ence + bank cubic meter of material will shrink to =.F compacted cubic meters as a result of compaction.

/ 5oad 5oad and and 2hrin 2hrinka kage ge (acto (actors rs *n performing earthmoving calculations, it is important to convert all material volumes to a common unit of measure.

















Engineering •

he shrinkage factor may be calculated by use of E1uation ? or @/

2hrinkage #actor 7 We Weight8&ank ight8&ank unit %olume 9 We Weight8com"acted ight8com"acted unit %olume

*E1/?+

or 2hrinkage #actor 7 , - shrinkage •

*E1/@+

%ank volume may be multiplied by the shrinkage factor to obtain compacted volume or compacted volume may be divided by the shrinkage factor to obtain bank volume.

E$am"le

















Engineering

Estimating Earthwork 3olume •

;hen planning or estimating an earthmoving pro>ect p ro>ect it is often necessary to estimate the volume of material to be excavated or placed as fill.

















Engineering –

4or more more comple complex x areas, areas, measure measure the depth depth at additio additional nal points points along the perimete perimeterr of the excavation and average all depths.

E$am"le  Estimate the volume of excavation required (bank measure) for the basement shown in 4igure. 5alues shown at each corner are depths of excavation. 6ll values are in meters



















Engineering –

!ross sections should be taken at frequent linear intervals and the volumes between locations computed.

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hese volumes are then added to find total trench volume.

















Engineering

E$am"le < 4ind the volume of excavation required for the area shown below. he figure at each grid intersection represents the depth of cut at that location. 3epths in meters.
















2olution !orner points @+.F ? +.=/ ? =.+ ? +.-- @ /.N= m


















Engineering

The Mass-Haul Diagram 0ass 3iagram# 6 graphical representation of the cumulative amount of earthwork moved along the centerline and distances over which the earth and materials are to be transported.





















































































































Chapter 6 Earthworks 4

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