Investigation of change in shear wave velocity with increasing applied stress for two samples from Holme Pierrepoint

The development of capability in the measurement of superficial deposit thickness has required
laboratory testing to integrate with values obtained from field trials of a number of
methodologies and equipment. The use of shear waves to detect the base of a deposit depends on
an accurate knowledge of the internal velocities of the material in the deposit. It is also important
to know the shear wave velocities of the materials at the deposit interface.
The site used for initial assessment of equipment and methodologies was a series of sand, silt and
gravel layers overlying a weathered mudstone. There are a number of interfingered facies within
the body of the deposit, which may have differing interval velocities. The object of this
laboratory study is to determine the shear wave velocities through undisturbed samples of the
deposit material and the underlying solid geology. The samples under test are silty fine sand and
the weathered mudstone. The gravel layers could not be sampled in an undisturbed state and
have not been included in this study.