PRINCIPLES AND APPLICATION OF STATIC CONE PENETRATION TEST

1. Presented by
Indranil banerjee
Roll No-CEM18005
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 cm2 into the subsurface . The cone is
penetrated at a constant rate of 1 cm/s.
During penetration following parameters
are recorded:
Cone tip resistance(qc): In the cone
head the Cone resistance (qc) is recorded
(in MPa) , which expresses the resistance
of the sediments to penetration .

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

6. Principles of cone penetration test
Higher friction ratio (Rf) and
lower cone tip resistance (qc)
denotes clayey soils, whereas
sands have lower friction ratio
(Rf ) and higher cone tip
resistance (qc).
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(Su)
 Soil sensitivity(St)
 Undrained shear strength ratio,(Su/σvo)
 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)

12. THANK YOU