Testing on the Thames
Constructive Evaluation were recently commissioned to undertake an unusual Ground Investigation project – providing design parameters for the construction of a new shipping jetty, with an approach ramp adjacent to an existing jetty over the River Thames in Northfleet, Kent. This involved carefully cutting through the existing concrete jetty over the River Thames using our hydrostatic coring equipment to determine the top level of the chalk, the thickness of its weathered section and overlying deposits. With our hydrostatic coring apparatus, we are adept at handling the extreme demands posed by surfaces offering varying levels of resistance. The coring of hardstanding concrete, but also softer soils such as clay, sand and river sediment are a breeze for our hydrostatic coring setup.
Following the concrete coring, we carried out a combination of Cable Percussive and Rotary Coring drilling. Cable Percussive Drilling, also known as Shell and Auger, enables the creation of boreholes in superficial deposits or weak rock, such as chalk, up to a depth of 90m (depending on ground conditions). The Rotary Coring rig allows the drilling of deep boreholes and sampling of otherwise unreachable competent rock typically found at greater depths. These methods were utilised so as to sample the river sediments and obtain core samples of the chalk bedrock below. Casing was dropped through the jetty prior to drilling to provide support within the soft river sediments.
Once back in the office, the opportunity was taken for some further detailed chalk logging, as well as to select key samples from a selection of twenty, for a range of geotechnical and geo-environmental tests including Moisture Content, Particle Size Distribution, Sedimentation, Shear Strength, Triaxial Compression, & Particle Densities. For more information on these tests, visit our lab testing page.
The client was pleased with our findings and has heeded our advice. Thanks to our comprehensive reporting, construction has already begun on the new jetty.
If you have a similar project, want a competitive quote or to discuss our services with one of our qualified surveyors or engineers please contact us here . If you would like more information on the other drilling services we offer, click here.
