CONE PENETRATION TEST

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PRESENTATION ON PRINCIPLES AND APPLICATION OF
STATIC CONE PENETRATION TEST

• Presented by
• Indranil banerjee
• Roll No-CEM18005
• Department of Civil Engineering
• Tezpur university
• Autumn 2018

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CONTENT

• Introduction
• Principles
• Applications
• Reference

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INTRODUCTION

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

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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 .

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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

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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.

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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.

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Applications of CPT
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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.

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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/svo)
• Stress history , overconsolidation ratio (OCR)

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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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THANK YOU