Dynamic Sampling and Probing
Also known as windowless sampling or window sampling, dynamic sampling forms a fundamental part of contemporary ground investigation.
The dynamic sampling rig can access restricted areas and causes minimal site disturbance. In-situ Standard Penetration Tests (SPTs) can be undertaken using the dynamic sampling rig to provide information for foundation design. Gas/ groundwater monitoring wells and instrumentation can also be installed in the boreholes.
Depths of up to 6m can typically be achieved using dynamic sampling techniques. Greater depths can be attained by dynamic probing using the same rig and provides a relative strength with depth profile.
On sites where access is particularly restricted, hand-held (jack-hammer) window sampling or air probe techniques can be used.
Dynamic Sampling was Preferred Method of Investigation in Devon
Dynamic sampling (windowless sample boreholes) was utilised in a scheme of works for the proposed stabilisation and reinstatement of a quay wall. This was the preferred method for the initialgeotechnical investigationat this site, as they allowed representative samples of the near surface soils to be obtained, facilitated Standard Penetration Tests (SPTs) and were able to be progressed down to depths of 6m-8m to determine the presence of engineering rock-head, all whilst keeping site disturbance and the areal extent of the site works to a minimum, allowing the adjacent car park to be in continued use without the need for closure.
On completion of the ground investigation, the boreholes were either installed with monitoring wells, to facilitate long-term groundwater and/ or ground gas monitoring, or backfilled with natural arisings prior to reinstatement.