cone Penetration test

PRINCIPLES AND APPLICATION OF STATIC CONE PENETRATION TEST

1. PRESENTATION ON PRINCIPLES AND APPLICATION OF STATIC CONE PENETRATION TEST Presented by Indranil banerjee Roll No-CEM 18005 Department of Civil Engineering Tezpur university Autumn 2018

2. CONTENT Introduction Principles Applications Reference

3. INTRODUCTION Static cone penetration test is an in-situ penetration test which is used to determine the soil stratigraphy .

4. Principles of cone penetration test CPT surveying involves the penetration of a metal electrical cone with a surface of 10 cm 2 into the subsurface . The cone is penetrated at a constant rate of 1 cm/s. During penetration following parameters are recorded: Cone tip resistance(q c ): In the cone head the Cone resistance (q c ) is recorded (in MPa ) , which expresses the resistance of the sediments to penetration .

5. Principles of cone penetration test Sleeve friction( f s ) : The sleeve friction ( f s ) is also recorded in ( MPa ); indicative of adhesive strength of the material. Friction ratio ( R f ): From the cone resistance and the sleeve friction the friction ratio ( R f ) can be calculated as: R f =[( f s /q c ) x 100]

6. Principles of cone penetration test Higher friction ratio ( R f ) and lower cone tip resistance (q c ) denotes clayey soils, whereas sands have lower friction ratio ( R f ) and higher cone tip resistance (q c ). Pore water pressure : It is another useful parameter that can be recorded in CPT surveying (the so- called piezocone test) is the pore pressure u.

7. Applications of CPT Direct measurements are used to estimate geo-technical parameters, which can then be used in an analysis. CPT results can also be directly applied into geotechnical engineering designs.

8. Applications of CPT

9. Applications of CPT The primary application of the CPT is for soil profiling and determining soil type using soil behavior type (SBT) graphs that has been developed for this application .The numerical values are plotted on SBT graphs, from which the zone is identified.

10. Applications of CPT CPT data are used to estimate the following geotechnical parameters of materials, which then can be used in various geotechnical analyses: Undrained shear strength(S u ) Soil sensitivity(S t ) Undrained shear strength ratio,(S u / σ vo ) Stress history , overconsolidation ratio (OCR)

11. Reference Basic and applied soil mechanics( Gopal Ranjan ASR Rao ) Foundation analysis and design (Joseph E. Bowles) Wikipedia(Internet) Geology National Engineering handbook(part 631)

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