Geotechnical Engineering Ltd. were contracted to conduct a site investigation comprising four dynamic-cone penetrometer (DCP) tests; two on each platform, with the results reported as factual data.
Working on a live station platform requires consideration of several issues;
To minimize the disruption to the public, the locations for the site investigation were chosen to be away from access to the station and away from the main walkways, limiting the potential contact the public had with the works.
To prevent damage to the platform itself, the equipment used was a DCP not a drill rig. A drill rig would require an inspection pit, the borehole setup would cause greater disruption in the station and the weight of the rig could potentially cause the concrete slabs to break. For the same reason, the use of hand-tools rather than a hydraulic breaker was preferred for the removal of the concrete slabs. Another reason for using the DCP was to collect a substantial data set in relatively little time.
Additionally, to ensure the swift completion of works, the site was prepared ahead in readiness for the DCP tests to be carried out, including fencing-off locations and removal of concrete slabs.
The setup and recording of data was completed by our engineering geologist and the data was presented in both pdf format and as AGS data.