The document discusses the objectives and methods of geotechnical investigations for infrastructure projects. It explains that geotechnical investigations are needed to determine the engineering properties and characteristics of soil and rock in order to design foundations, embankments, and structures. The investigations include site reconnaissance, exploratory drilling or digging, laboratory testing of soil samples, and analysis of soil properties including bearing capacity, moisture content, swelling, and shear strength. The results are used to design foundations and recommend construction parameters.

1. Prepared by: M.A.Monayem MIEAust,CPEng.

2. Project Background
1. Existing road and bridges are mostly with 2 lane carriageway.
2. All geotechnical investigations were carried out during
the construction of existing roads.
3. A detail road and bridge condition survey has been initiated
by the consultant team.
Prepared by: M.A.Monayem MIEAust,CPEng
GEOTECHNICAL INVESTIGATION

3. 1. Ascertain the physical, mechanical properties of soil for
foundation and embankment design.
2. To know the depth and thickness of various soil strata.
3. Study of groundwater level.
Prepared by: M.A.Monayem MIEAust,CPEng
OBJECTIVES OF GEOTECHNICAL INVESTIGATIONS
4. Determination of engineering properties of soil and rock
materials.
5. In-situ properties by field test.

4. Prepared by: M.A.Monayem MIEAust,CPEng
GEOTECH-INVESTIGATION FOR STRUCTURES
To determine the characteristics of in-situ materials for
foundation design and estimation of safe bearing capacity
or pile/footing load capacity.

5. Prepared by: M.A.Monayem MIEAust,CPEng
SITE INVESTIGATION
Site investigation consists of:
-Preliminary investigation(Review of data
of existing embankment/structures)
-Site reconnaissance through actual site
inspection.

6. Prepared by: M.A.Monayem
MIEAust,CPEng
STAGES OF INVESTIGATION
The three important stages of geotechnical investigations:
- Planning (Minimize the cost, quality and quantity of
investigation)
- Execution (Collection of disturbed and undisturbed
samples, in-situ test of surface materials, groundwater
study, laboratory test of samples etc.)
- Reporting ( field and lab tests, analysis of data,
preparation of charts, tables and graphs, bore logs,
data interpretation, calculations and recommendations)

7. Prepared by: M.A.Monayem
MIEAust,CPEng
METHODS OF EXPLORATION
- Direct Methods (Test Pits, Depth upto 1.5 m),
- Semi-Direct Methods
-Auger Boring
-Shell Boring
-Wash Boring
-Percussion drilling
-Rotary Drilling

8. Prepared by: M.A.Monayem
MIEAust,CPEng
Performance of sub-grade materials generally depend
on three basic characteristics:
- Load bearing Capacity
- Moisture Content
- Shrinkage and Swelling
CHARACTERSTICS OF SUB-GRADE
MATERIALS

9. Prepared by: M.A.Monayem
MIEAust,CPEng
For sub-grade stiffness/strength chacterization
laboratory confirmatory test by:
-CBR (California Bearing Ratio, AASHTO T193).
LAB CONFIRMATORY TEST FOR SUB-
GRADE STIFFNESS/STRENGTH

10. Prepared by: M.A.Monayem MIEAust,CPEng
For new embankment and slope design the following
Parameters of soil are to be examined:
- CBR
- Swelling shrinkage properties for soil.
- Shear parameters of embankment soil and
foundation sub-soil.
- Atterberg limit.
- Examination of groundwater condition etc.
GEOTECHNICAL INVESTIGATION FOR
NEW EMBANKMENT

11. Prepared by: M.A.Monayem
MIEAust,CPEng
GEOTECHNICAL INVESTGATIONS AND
REFERENCE STANDARDS
Test Reference Standards
Standard Penetration Test ASTM D 1586
Natural water content ASTM D 2216
Specific Gravity ASTM D 854
Atterberg Limits ASTM D 4318
Grain Size Analysis ASTM D 422
Unit Weight ASTM D 4718
Unconfined Compression Test ASTM D 2166
Consolidation Test ASTM D 2435
Triaxial Compression Test ASTM D 2850
Direct Shear Test ASTM D 3080

12. Prepared by: M.A.Monayem
MIEAust,CPEng
Geotechnical investigation covers from top to
deep layers of soil for estimation and planning
for needful support of embankment and
foundation of the structures of the project.
CONCLUSION

13. Prepared by: M.A.Monayem
MIEAust,CPEng
Thank you all for participating with us.