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 3


Dissipation test

          DISSIPATION TEST   3.1 

In a dissipation test the porewater pressure change is obtained by recording the values of the pressure against time during a pause in pushing and while the cone penetrometer is held stationary. It is practical to use either a logarithmic or square root scale for the time factor (Figure 10).
Dissipation tests are often presented with the normalised
excess porewater pressure plotted against the log or square root of the time (Figure 11).
Rate of consolidation parameters may be assessed from the piezocone test using the value t50. In this case, t50 is the time for 50% dissipation of excess porewater pressure. Figure 12 shows one of many charts available for determining the consolidation factor, ch.

<< Previous PageNext Page >>