SITE ENGINEERING DIPLOMA KEJURUTERAAN AWAM PKK
C5306 SITE ENGINEERING 1. SITE INVESTIGATION (7 hours) 2. INTRODUCTION TO FOUNDATION (2 hours)
3. BEARING CAPACITY AD DESIGN OF SHALLOW FOUNDATION (5 hours) 4. DEEP FOUNDATION (11 hours) 5. SETTLEMENT (5 HOURS)
Evaluation Continuous Assessment (CA) • Quiz - 5 • Assigment/Tutorial – 4 • Test – 3
(50%) (20%) (30%) (50%)
Final Examination (FE)
(50%)
TOPIC 1
SITE INVESTIGATION
Course content UNDERSTAND THE OBJECTIVES AND WORK PROCEDURE IN SITE INVESTIGATION. • DEFINE SITE INVESTIGATION • STATE OBJECTIVE OF SITE INVESTIGATION BASED ON BS5930 (1981) • EXPLAIN BRIEFLY THE WORK PROCEDURE IN SITE INVESTIGATION
Course content UNDERSTAND PROSEDURE OF PRELIMINARY WORK IN SITE INVESTIGATION UNDERSTAND PROGRAMMED PLANNING AND SCOPE OF SITE INVESTIGION UNDERSTAND FIELD TEST UNDERSTAND THE CRITERIA IN DETERMINING NUMBER AND TYPES OF SAMPLES EXPLAIN TYPE OF SAMPLES
Course content UNDERSTAND THE CONTENT OF SITE INVESTIGATION REPORT USE THE GIVEN CONCEPT IN PERFORMING PRELIMINARY ON-SITE SURVEY
Define site investigation
MJ TOMLINSON (2001) FOUNDATION DESIGN AND CONSTRUCTION
A site investigation in one form or another is always required for any engineering or building structure. The investigation may range in scope from a simple examination of the surface soils with or without a few shallow trial pits, to a detailed study of the soil and ground water condition to a considerable depth below the surface by means of boreholes and in-situ and laboratory test on the materials encountered.
SOIL INVESTIGATION • In the evaluation of an area for construction of buildings or other structures, or as a source of construction material, the soil condition must be investigated before any detailed design are made. • A soil investigation involves field sampling
SOIL INVESTIGATION • A soil investigation involves 1. field sampling and testing 2. Laboratory analysis 3. And preparation of report • The planning and evaluation of field work are aided by a knowledge of the mechanics of soil deposits formation Harold N. Atkins. Highway Materials, Soils, and Concretes (Fourth Edition). (2003)
FIELD INVESTIGATION TECHNIQUES • Soil investigation are conducted for most medium – to large – sized building, highways, bridges, dams, water control facilities, harbors, and other structures. • The purpose is to find the allowable bearing capacity for foundations, water resources, find aggregate deposits, estimate infiltration and seepage rates, and to help assess land use capabilities.
The purposes of subsoil exploration (BRAJA M.DAS (2010) PRINSIPLES OF GEOTECHNICAL ENGINEERING)
1) Determining the nature of soil at the site and its stratification 2) Obtaining disturbed and undisturbed soil samples for visual identification and appropriate laboratory tests. 3) Determining the depth and nature of bedrock, if and when encountered
The purposes of subsoil exploration (BRAJA M.DAS (2010) PRINSIPLES OF GEOTECHNICAL ENGINEERING)
4) Performing some in situ field test, such as permeability test, vane shear test and SPT 5) Observing drainage condition from and into the site 6) Assessing any special construction problem with respect to the existing structure nearby 7) Determining the position of the water table
Objective of site investigation based on BS5930 (1981) 1. Suitability. To assess the general suitability of the site and environs for the proposed works including, where applicable, the implications of any previous use or contamination of the site. (Kesesuaian) 2. Design. To enable an adequate and economic design to be prepared, including the design of temporary works. (Rekabentuk)
Objective of site investigation based on BS5930 (1981) 3. Construction. To plan the best method of construction; to predict and provide against difficulties and delays that may arise during construction due to ground, groundwater and other local conditions; in appropriate cases, to explore sources of local materials for use in construction and to select sites for the disposal of waste or extra materials.
Objective of site investigation based on BS5930 (1981) 4. Effect of changes. To determine the changes that may arise in the ground and environmental conditions, either naturally or as a result of the works, and the effect of such changes on the works, on adjacent works, and on the environment in general. (perubahan pada tapak) 5. Choice of site. Where alternatives exist, to advise on the relative suitability of different sites, or different parts of the same site.
Objective of site investigation based on BS5930 (1981) 6. Existing works. Unless the contrary can be demonstrated, it should be assumed that site investigations are necessary in reporting upon the existing works and for investigating cases where failure has occurred.
Procedure in site investigation Preliminary study/Desk study Site survey
Programmed planning and scope of site investigation Soil investigation and soil sampling Laboratory testing Report preparation of site investigation Designing Re-investigation research during construction and supervision
DESK STUDY
• This involves collecting as much information as possible about the sit. • Sources include i. Geological maps ii. Survey map
DESK STUDY • Sources include i. Geological maps ii. Topography iii. Surface water & groundwater iv. Survey map v. Aerial photographs vi. Mining records vii. Previous site investigation for the site or adjacent site
DESK STUDY
SITE SURVEY • what is needed in light of existing information, provide specific rationale for the scope and methods of site investigation to make it possible for reviewers to assess the adequacy of the investigation. • Describe what was carried out. • Show location of test holes or pits or geophysical lines if any. Include field observations at the site, soils and existing conditions.
Programmed planning and scope of site investigation • After a site survey carried out, engineers (consultants) will design and scope of site investigation program. • At this stage, engineers will determine whether the data required by the designer. • The engineers next will choose the test-site (in-situ test) and laboratory data to meet the structural design for buildings, especially the basic types (type of foundation: shallow or deep foundation)
SOIL INVESTIGATION AND SOIL SAMPLING • Detailed investigation of the geological processes and the soil conditions beneath the surface of the hole by trial (trial pits), a bore hole (boreholes) and others. • Survey of ground water also, examining the damage to the nearby (e.g. deposition, structure and process of sampling locations). to determine in detail the geological structure of land including the thickness and type of soil.
SOIL INVESTIGATION AND SOIL SAMPLING • Investigation should be conducted to prove the validity of and expand the information collected earlier. • As a whole, information about land needed in order to determine the most suitable project, providing design and carry out the construction. For example, in construction work, when excavation work is carried, the knowledge of the bottom layer and the water in the soil needed for the following purposes:
Three steps of soil exploration BORING SAMPLING
TESTING
Drilling or advancing a hole in the ground Removing soil from the hole Determining characteristics or properties of the soil
LABORATORY TESTING • A preliminary examination of the nature and type of soil brought to the laboratory is very essential before deciding upon the type and number of laboratory tests. • Normally the SPT samples are used for this purpose. First the SPT samples should be arranged bore wise and depth wise. Each of the samples should be examined visually. A chart should be made giving the bore hole numbers and the types of tests to be conducted on each sample depth wise.
LABORATORY TESTING • An experienced geotechnical engineer can do this job with diligence and care. Once the types of tests are decided, the laboratory assistant should carry out the tests with all the care required for each of the tests. • The test results should next be set out on a suitable format bore wise and the soil is classified according to standard practice. The geotechnical consultant should examine each of the tests before being set out. Unreliable test results should be discarded.
LABORATORY TESTING 1. 2. 3. 4. 5. 6.
Grain size distribution - Mechanical analysis Liquid limit (LL) Plastic limit (PL) Specific gravity Natural water content Shear strength – unconfined compression - direct shear - Triaxial
LABORATORY TESTING 7. Compressibility – consolidation 8. Permeability 9. Compaction – standard proctor & moditied proctor 10. CBR 11. Shear strength (soft clay) – vane shear 12. Penetration test
Laboratory test related to soils investigation
TEST
SAMPLE REQUIRED DISTURBED OR UNDISTURBED
UNDISTURBED
SOILS COHESIVE
GRANULAR
Moisture content
X
X
X
Grain size
X
X
X
Atterberg limits
X
X
Relative density (G.S)
X
X
X X
Density (unit weight)
X
X
Unconfined compression
X
X
Triaxial compression
X
X
X
Direct shear
X
X
X
Consolidation
X
X
Vane shear
X
x
permeability
x
X
REPORT PREPARATION OF SITE INVESTIGATION • A report is the final document of the whole exercise of soil exploration. • A report should be comprehensive, clear and to the point. • A report writer should be knowledgeable, practical and pragmatic. • No theory, books or codes of practice provide all the materials required to produce a good report. It is the experience of a number of years of dedicated service in the field which helps a geotechnical consultant make report writing an art.
REPORT PREPARATION OF SITE INVESTIGATION • A good report should normally comprise the following: 1) A general description of the nature of the project and its importance. 2) A general description of the topographical features and hydraulic conditions of the site. 3) A brief description of the various field and laboratory tests carried out. 4) Analysis and discussion of the test results
REPORT PREPARATION OF SITE INVESTIGATION 5) Recommendations 6) Calculations for determining safe bearing pressures, pile loads, etc. 7) Tables containing bore logs, and other field and laboratory test results 8) Drawings which include an index plan, a siteplan, test results plotted in the form of charts and graphs, soil profiles, etc.
DESIGNING
• The design of the building structure can be made by the engineers. • The first structure to be designed is a basic building. With reference to the design load (structure plan), the limit soil deposition and soil type, foundation engineers will analyze and determine the appropriate type of foundation in the study area either in a shallow foundation or base.
DESIGNING
• If a soil layer is far from the ground, the basic choice (pile foundation) should be considered. To determine the basis of size or depth, the soil unit weight, cohesion and friction angle of soil should be obtained through the site investigation report.
RE-INVESTIGATION RESEARCH DURING CONSTRUCTION AND SUPERVISION Sometimes there are problems faced by the contractors during the construction being carried out as an example of damage to piles during installation. thus, a review of the basic structure of the building must be done to design the pile foundation is involved again.
Discussion • Site investigation should be split up into three section; 1. A walk-over survey 2. An initial desktop study 3. Field investigations using trial pits or boreholes Discuss in group WHAT information should be collect in a walk-over survey.
Discussion • Describe site investigation? • What information usually required in soils investigations includes? • Describe the technique sampling during soil investigation?
ASSIGNMENT 1 GROUP
TOPIC
1
Explain boring borehole method a. Hand Auger b. Rotary drilling c. Hammer drilling d. Wash boring e. Core drilling
2
Explain field test carried out on site Standard Penetration Test (SPT)
3
Explain field test carried out on site Cone Penetration Test (CPT)
4
Explain field test carried out on site Plate Load Test
5
Explain field test carried out on site Trial Test
ASSIGNMENT 1 GROUP
TOPIC
6
Explain methods of observation and measurement of ground water, methods of measuring water pressure • Vertical pipe • Piezometer
7
Explain types of sampler • Thin walled sampler • Open drive sampler • Separate drum sampler/split spoon sampler
8
Explain types of sampler • Stationary piston sampler • Continuous sampler • Compressed air sampler
PROSEDURE OF PRELIMINARY WORK 1. Lists important information for compilation 2. Identify necessary equipment for site investigation exercise 3. Explain important points carried out during programmed planning and scope of site investigation
INFORMATION REQUIRED IN SOIL INVESTIGATION • Depth, thickness and properties of each soil layer • Location of groundwater table • Depth to bedrock
EQUIPMENT FOR SITE INVESTIGATION • Samples equipment • In place testing (field) 1. Standard penetration test 2. Vane shear test 3. Cone penetration test 4. Pressuremeter test – predicting settlement and shear strength properties of the soil 5. Piezometer - groundwater
BORING BOREHOLE METHODS 1. Hand auger – the sample taken from the soil is brought up by the auger (the sample is disturbed) 2. Rotary drilling 3. Hammer drilling 4. Wash boring 5. Core drilling
FIELD TEST 1. Standard Penetration Test (SPT) 2. Cone Penetration Tets (CPT) 3. Plate Load Test 4. Trial Test Observation of ground water 1. Vertical pipe 2. Piezometer
FIELD TEST Standard Penetration Test (SPT) This test is the most common strength test conducted in field. It is used with all soil except gravel and it often used directly for the design of foundation.
FIELD TEST Cone Penetration Tets (CPT) the cone itself is to forced an additional distance by inner rods, without the drill rods moving through the soil.
CRITERIA IN DETERMINING THE NUMBER OF SAMPLING • The number and depth of test holes depend on the structure to be built, the type of soil, and the variation in the soil profile found. 1. One story buildings Test holes are drilled 30-60m apart (distant) to a depth of 6-10m, with one deeper hole to check the deeper soils.
CRITERIA IN DETERMINING THE NUMBER OF SAMPLING 2. Four story buildings Test holes are drilled 15m-30m apart (distant) to a depth of 10-15m, with some holes to a depth one and one-half times the width of the building and at least one deep hole to bedrock 3. Highways Test holes are drilled approximately 300m apart to depth of 3m below subgrade level
CRITERIA IN DETERMINING THE NUMBER OF SAMPLING • Samples and field tests (for the first few holes) are taken in every soil layer or every 1.5m (5ft), whichever is less.
TYPE OF SAMPLING 1. 2. 3. 4. 5. 6.
Thin walled sampler/shelby tube Open drive sampler Separate drum sampler/split spoon sampler Stationary piston sampler Continuous sampler Compressed air sampler
TYPE OF SAMPLING Thin walled sampler/shelby tube The sampler is attached to drill rods, lowered to the bottom of the hole, and pushed into the soil in one smooth motion; the sample is waxed when removed; the sample is undisturbed. This technique is used only in clays and silts Separate drum sampler/split spoon sampler The spoon is lowered to the bottom of the hole, attached the drill rods, and driven into the soil; the sample is disturbed. This technique is use d in all soils
SITE INVESTIGATION REPORT 1. Content of Site Investigation Report 2. Borehole logs
SITE INVESTIGATION REPORT Content of Site Investigation Report • Summary of the test program • General description of the soil condition • Detailed analysis of each type of soil • Recommendations for design (as required) • Test hole logs and the soil profile
SITE INVESTIGATION REPORT Borehole logs include: 1. Sample number, depth and type 2. Field test, depth and result 3. Depth to layer changes 4. Field soil description a) Type of soil grains b) Moisture conditions c) Consistency or density d) Seams (layers) and stratification e) Other distinguishing features
Example map showing boring location on 150-ft by 300-ft
BORING LOG SHEET
NUMBER AND DISPOSITION OF TEST LOCATION • For compact building site covering an area of about 0.4 hectare, one bore hole in each corner and one in the centre should be adequate • For smaller and less important building, even one hole in the centre will suffice • For very large areas covering industrial and residential colonies, the geological nature of the terrain will help in deciding the number of bore holes.
In general, dynamic or static cone may be performed at every 100m by dividing the area in grid pattern and the number of bore holes may be decided by examining the variation in the penetration curves. V.N.Vazirani : Handbook of civil Engineering , Khanna Publishers (2008)
DEEP OF BORINGS FOR FOUNDATION • Explore soil to the depth to which it will be significantly stressed. • This is often taken as the depth at which the vertical total stress increase due to the foundation is equal to 10% of the stress applied at foundation level
Borehole depths for foundations
ASSIGNMENT 1 (GROUP) Explain boring borehole method • Hand Auger • Rotary drilling • Hammer drilling • Wash boring • Core drilling
ASSIGNMENT 1 (GROUP) Explain types of sampler • Thin walled sampler • Open drive sampler • Separate drum sampler/split spoon sampler • Stationary piston sampler • Continuous sampler • Compressed air sampler
Explain field test carried out on site. Explanations include the standard of the test, method on the site and diagram/picture that equipment. • Standard Penetration Test (SPT) • Cone penetration test (CPT) • Plate load test • Trial test • Vertical pipe • Piezometer
