Geotechnical Instrumentation & Monitoring

Geotechnical Instrumentation & Monitoring

Causeway Geotech Ltd have the capability to install and subsequently monitor a wide range of geotechnical and geoenvironmental instrumentation.
These can be for a variety of applications, such as groundwater and ground gas monitoring and ground movement.

We are able to install a full range of groundwater and gas monitoring instruments, including standard standpipe piezometers set in sand cells within boreholes, and slotted standpipes typically from 19mm up to 50mm internal diameter, although alternative sizes are also available. Multilevel monitoring and sampling installations may also be provided, where several discrete levels of interest may be monitored from a single borehole. Groundwater levels are measured using a graduated dipmeter and ground gases monitored using an infra-red analyser. Multiphase dip meters are employed on sites where there is potential free product within the water column. When measuring gas concentrations, both initial and steady state levels are recorded together with atmospheric and installation pressure and flow rate – all in accordance with the CIRIA guidance. If long term groundwater information is required or the variation in water level over a tidal cycle, electronic data-loggers are installed in the piezometers/standpipes which are later collected and the data downloaded.

In addition to conventional groundwater piezometers, vibrating wire piezometers may be installed. These are particularly useful where monitoring of piezometric levels in low permeability soils are required. The instruments are grouted into the boreholes and may either be monitored manually at discrete times, or by using automated data recorders which can record the piezometric data at prescribed intervals over days, weeks, or even months.

With regard to ground movement, one of the simplest techniques is installing and monitoring the level of settlement plates set into the ground. More sophisticated monitoring of ground movements includes the use of extensometers, with target magnets placed at multiple levels in boreholes, and borehole inclinometers, commonly used in slope stability analysis, which are monitored using a biaxial probe. Causeway Geotech have the capabilities to both install such instrumentation, as well as provide the professional services for monitoring and interpretation of the data produced thereafter.