importance of geotechnical investigation for foundation design

IMPORTANCE OF GEOTECHNICAL INVESTIGATIONS FOR FOUNDATION DESIGN : 

IMPORTANCE OF GEOTECHNICAL INVESTIGATIONS FOR FOUNDATION DESIGN PRESENTER: SHAHZADA FAIZ RASOOL 2007-MS-GEO-23

CONTENTS : 

CONTENTS WHAT IS FOUNDATION DESIGN? FOUNDATION DESIGN METHODOLOGIES FOUNDATION DESIGN PARAMETERS GEOTECHNICAL INVESTIGATIONS CONCLUSIONS

GEOTECHNICAL INVESTIGATIONS VsFOUNDATION DESIGN : 

GEOTECHNICAL INVESTIGATIONS VsFOUNDATION DESIGN

WHAT IS FOUNDATION DESIGN? : 

WHAT IS FOUNDATION DESIGN? In the perspective of the geotechnical engineering the foundation design comprises of evaluation of the following; The parameters of soils which influence the foundation design. The foundation depth. The foundation dimensions; and The bearing pressure of soils to ensure the safety of the foundations against shear failure and excessive settlement. Construction aspects of the foundations.

FOUNDATION DESIGN METHODOLOGIES : 

FOUNDATION DESIGN METHODOLOGIES Foundations design is based on; Shear Failure Criteria; and Settlement Criteria Various researchers have developed a variety of methods to evaluate the foundation bearing pressure against the above criterions; like

SHALLOW FOUNDATIONS : 

SHALLOW FOUNDATIONS

Slide 8: 

Terzaghi’s Bearing Capacity Equation: FOUNDATION DESIGN METHODOLOGIES

FOUNDATION DESIGN METHODOLOGIES : 

FOUNDATION DESIGN METHODOLOGIES Temoshenko And Goodier’s Equation For Immediate Settlement Evaluation:

FOUNDATION DESIGN METHODOLOGIES : 

FOUNDATION DESIGN METHODOLOGIES Equation For Evaluation of Consolidation Settlements:

FOUNDATION DESIGN METHODOLOGIES : 

FOUNDATION DESIGN METHODOLOGIES

FOUNDATION DESIGN METHODOLOGIES : 

FOUNDATION DESIGN METHODOLOGIES

FOUNDATION DESIGN METHODOLOGIES : 

FOUNDATION DESIGN METHODOLOGIES

FOUNDATION DESIGN METHODOLOGIES : 

FOUNDATION DESIGN METHODOLOGIES DEEP FOUNDATIONS

FOUNDATION DESIGN METHODOLOGIES : 

FOUNDATION DESIGN METHODOLOGIES TOMLINSON METHOD

Slide 16: 

Where FOUNDATION DESIGN METHODOLOGIES

FOUNDATION DESIGN METHODOLOGIES : 

FOUNDATION DESIGN METHODOLOGIES

FOUNDATION DESIGN METHODOLOGIES : 

FOUNDATION DESIGN METHODOLOGIES

FOUNDATION DESIGN METHODOLOGIES : 

FOUNDATION DESIGN METHODOLOGIES

FOUNDATION DESIGN METHODOLOGIES : 

FOUNDATION DESIGN METHODOLOGIES

FOUNDATION DESIGN PARAMETERS : 

FOUNDATION DESIGN PARAMETERS Standard Penetration Resistance “N-value” Bulk Density of Soils “γ” Undrained Compressive Strength “CU” Angle of Internal Friction “φ” Compression Index “Cc” Initial Void Ratio “eo” Modulus of Elasticity “E” Poison’s Ratio “μ”

GEOTECHNICAL INVESTIGATIONS : 

GEOTECHNICAL INVESTIGATIONS Geotechnical investigation is accomplished by ; Field Investigation/ In situ Testing. Laboratory Testing.

GEOTECHNICAL INVESTIGATIONS : 

GEOTECHNICAL INVESTIGATIONS

GEOTECHNICAL INVESTIGATIONS : 

GEOTECHNICAL INVESTIGATIONS Field Investigation/ In situ Testing. Most common types of in-situ testing that is generally carried out, Standard Penetration Test (SPT). Cone Penetration Test (CPT). Excavation Of Test Pits

Standard Penetration Test (SPT) : 

Standard Penetration Test (SPT)

Standard Penetration Test (SPT) : 

Standard Penetration Test (SPT)

Standard Penetration Test (SPT) : 

Standard Penetration Test (SPT) Hand Auger/Light percussion Drilling

Standard Penetration Test (SPT) : 

Standard Penetration Test (SPT) Straight Rotary Drilling Rig

Cone Penetration Testing (ASTM D 5778) : 

Cone Penetration Testing (ASTM D 5778)

Cone Penetration Testing (ASTM D 5778) : 

Cone Penetration Testing (ASTM D 5778)

EXCAVATION OF TEST PITS : 

EXCAVATION OF TEST PITS

EXCAVATION OF TEST PITS : 

EXCAVATION OF TEST PITS

GEOPHYSICAL INVESTIGATIONS : 

GEOPHYSICAL INVESTIGATIONS Stratification of Subsurface Materials Profile Top of Bedrock Depth to Groundwater Limits of Types of Soil Deposits Rippability of Hard Soil and Rock Locate Voids, Buried Utilities, Substructures Shear Velocity and Modulus Properties

GEOPHYSICAL INVESTIGATIONS : 

GEOPHYSICAL INVESTIGATIONS

GEOPHYSICAL INVESTIGATIONS : 

GEOPHYSICAL INVESTIGATIONS

GEOPHYSICAL INVESTIGATIONS : 

GEOPHYSICAL INVESTIGATIONS

GEOPHYSICAL INVESTIGATIONS : 

GEOPHYSICAL INVESTIGATIONS

GEOTECHNICAL INVESTIGATIONS : 

GEOTECHNICAL INVESTIGATIONS LABORATORY TESTING. Following tests are generally carried out on disturbed or undisturbed samples obtained as a result of field investigation,

GEOTECHNICAL INVESTIGATIONS : 

GEOTECHNICAL INVESTIGATIONS 1.Sieve Analysis, Hydrometer Analysis & Atterberg Limits

GEOTECHNICAL INVESTIGATIONS : 

GEOTECHNICAL INVESTIGATIONS Unconfined Compression Test It is usually performed on undisturbed soil sample(UDS). It gives unconfined compressive strength(qu) undrained shear strength CU =qu/2

GEOTECHNICAL INVESTIGATIONS : 

GEOTECHNICAL INVESTIGATIONS Direct Shear Test It is usually performed on granular materials. It gives shear strength parameters (c & Ф).

GEOTECHNICAL INVESTIGATIONS : 

GEOTECHNICAL INVESTIGATIONS Consolidation and Swell Test It gives the parameters used in consolidation settlement Analysis like Compression index ( CC ) Recompression index ( Cr ) Void ratio (e0) Co-efficient of volume change ( mv)

GEOTECHNICAL INVESTIGATIONS : 

GEOTECHNICAL INVESTIGATIONS Test for determination of Chemical Contents etc In this test usually sulphate , chloride & organic contents are Determined.

CONCLUSION : 

CONCLUSION Evaluation of precise soil parameters have strong effect on foundation design of the structures. Selection of an appropriate design method on the basis of investigated parameters. Shallow investigation “Testpit” gives necessary information about the top soil/overburden like “Indication of weak and low strength strata for improvement”. Justified soil parameters for design can only be provided by well planned geotechnical investigation. Briefly we can say at the expense of little cost (Generally 0.1 to 0.5 % of the project cost) and time in the form well planned geotechnical investigation at the beginning of a project can result in an economical and efficient design .

THANK YOU : 

THANK YOU