Buy the Book

Published By Lankelma

Lankelma is the foremost contractor for onshore in-situ soil testing in the UK. An acknowledged specialist in CPT, Lankelma also offers a worldwide consultancy and training service.

A.P. van den Berg develops, designs and manufactures geotechnical and environmental soil investigation equipment for onshore and offshore applications. Specialists in CPT systems and equipment.


Gardline Geosciences offers worldwide marine geotechnics, in-house consutancy and services with marine investigations ranging from nearshore to full ocean depth (down to 3000m).

About the Author

Hans Brouwer studied civil engineering at Delft University in The Netherlands. He has worked as a part-time lecturer at Amsterdam Polytechnic and was senior partner in a structural engineering consultancy. He has written a standard textbook in Dutch about the design of building foundations. He now lives in England where he writes technical textbooks in English, hopefully to reach a bigger readership.

Chapter 1



      GLOSSARY   1.4

This glossary contains the most frequently used terms related to CPT and CPTU.
The part of the Cone penetrometer on which the end bearing is developed

Cone penetrometer
The assembly containing the cone, friction sleeve, any other sensors and
measuring systems, as well as the connections to the push rods

Cone resistance, qc
The total force acting on the cone, Qc, divided by the projected area of the cone,
Ac; (qc = Qc / Ac)

Corrected cone resistance, qt
The cone resistance, qc, corrected for porewater pressure effects

Corrected sleeve friction, ft
The sleeve friction corrected for porewater pressure effects on the ends of the
friction sleeve

Data acquisition system
The system used to measure and record the measurements made by the cone

Dissipation test
A test when the decay of the porewater pressure is monitored during a pause in

Filter element
The porous element inserted into the cone penetrometer to allow transmission of
the porewater pressure to the pore pressure sensor, while maintaining the correct
profile of the cone penetrometer

Friction ratio, Rf
The ratio, expressed as a percentage, of the sleeve friction, fs, to the cone
resistance, qc, both measured at the same depth; Rf = (fs / qc).100

Friction reducer
A local enlargement on the push rod surface, placed at a distance above the cone
penetrometer, and provided to reduce the friction on the push rods

Friction sleeve
The section of the cone penetrometer upon which the sleeve friction is measured

Size classification for rotary drill casing

Net cone resistance, q n
The corrected cone resistance minus the vertical total stress, qn = qtσvo

Net pore pressure, Δu
The measured pore pressure less the equilibrium pore pressure, Δu = u – uo

Normalised cone resistance, Qc or Qt
The cone resistance expressed in a non-dimensional form and taking account of
stress changes in situ, Qc = (qc – σvo) / σvo, or when the corrected cone
resistance is used Qt = (qt – σvo) / σ'vo. Where σvo and σ'vo are the total and
effective vertical stress respectively

Normalised friction ratio, Fr
The sleeve friction normalised by the net cone resistance

A cone penetrometer containing a pore pressure sensor

Pore pressure, u
The pore pressure generated during penetration and measured by a pore
pressure sensor. u1 when measured on the cone, u2 when measured just behind
the cone and u3 when measured just behind the friction sleeve

Pore pressure ratio, Bq
The net pore pressure normalised with respect to the net cone resistance,
Bq = Δu/qn

Push rods
The thick-walled tubes or rods used for advancing the cone penetrometer

Thrust machine (rig)
The equipment, which pushes the cone penetrometer and push rods into the

Sleeve friction, fs
The total frictional force acting on the friction sleeve, Fs, divided by its surface
area, As; (fs = Fs / As)

<< Previous PageNext Page >>