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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 5

Sampling probes

Shelby soil sampler

General principles
The Shelby sampler (Figure 44) is a thin-walled soil sampling system. The system is used to sample soils that are particularly sensitive to sampling disturbance as it has a very low wall thickness-to-sample area ratio. The sampler consists of a thinwalled steel tube whose lower end is shaped to form a cutting edge. It is pushed into the soil by continuous static thrust from a hydraulic jack.
This sampler is usually only suitable for cohesive soils up to a firm-to-stiff consistency and free from large particles. It normally gives Class 1 samples of fine cohesive soils, including sensitive clays. Samples of 75, 100 or 150 mm in diameter can be obtained. The thin-walled Shelby sampler is not fitted out with a core catcher. However, a thicker-walled sampler with a core catcher is available. 
It should be noted that disturbance occurs at the base of the borehole in
weak soil below a certain depth due to stress relief resulting from
reduced over-burden pressure. Therefore, pushing the Shelby sampler
in using CPT equipment can overcome this to some degree.
At the end of the sampling process the thin steel tube containing the
sample is removed from the sampler head, waxed, capped at both ends
and labelled. The steel tube is used as a container to transport the
sample to the laboratory thus avoiding any damage to the sample.
Cohesive soils
The Shelby sampler is ideally used for normally-consolidated and over-
consolidated cohesive soils such as London Clay. It is not suitable for
granular non-cohesive soils. The disadvantage of the Shelby sampler –
in comparison to the Mostap sampler which can take samples at
preselected depths – is that it has an open end (no cutting mouth) so it
is necessary to start from ground level or pre-drill a borehole. Further
problems are encountered where the sample hole does not remain
open. In these situations the hole must be cased to prevent sampling of
‘fall-in’ materials. 
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