Geotechnical Monitoring & In Situ Testing

The Role of Engineering Geologist and Geotechnical Engineers

 

Engineering geology and geotechnics are a crucial aspect of construction and development projects, playing a vital role in ensuring the stability and safety of structures. G&J's engineering geologists and geotechnical engineers specialise in the assessment of soil, rock, and groundwater conditions to provide appropriate solutions that meet Client and Regulator requirements. Their expertise is essential in managing geotechnical risks and providing sustainable solutions for clients.

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​By providing expert geotechnical support, G&J can help clients avoid costly delays and ensure that projects are completed on time and within budget.

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G&J Geotechnical Testing and Monitoring

 

​​​​G&J offers a range of geotechnical monitoring and in-situ testing either through our in-house capability or in collaboration with our approved specialist contractors.

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G&J’s in-house capabilities include the following areas:

• Periodic or continuous groundwater level and porewater pressure monitoring, including the use of simple standpipe observation wells, to downloadable ‘divers’, to vibrating wire piezometers;

• Down-borehole inclinometer monitoring to measure ground movement for slope stability assessments;

• Down-borehole extensometer monitoring to measure ground movement for settlement assessments;

• Hand-shear vane testing of cohesive soils, to assess their undrained shear strength;

• TRL Dynamic Cone Penetrometer (DCP) testing to assess the in-situ strength or CBR of shallow soils, and variations within them;

• Soakaway testing to BRE Digest 365 in trial pits or falling head tests in boreholes, to indicate a soil’s permeability.

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G&J can also specify, arrange and supervise:

• Earthworks compliance testing (including core cutter and/or sand replacement tests, plate load tests, CBR testing, Nuclear Density Meter (NDM) testing, and longer-term zone/dummy foundation testing);

• Penetration testing, such as heavy dynamic probing and standard penetration tests (SPT);

• Non-intrusive geophysical surveys such as ground penetrating radar, ground conductivity mapping or resistivity profiles, to help identify variations in the ground, such as changes in geology or the presence of man-made hazards such as old sub-structures or mine shafts;

• Cone Penetration Testing (CPT) to provide almost continuous data on properties such as soil strength and porewater pressure variation with depth;

• Ground settlement monitoring, often performed as part of an earthworks project or when investigating ground subsidence.

• Ground vibration monitoring, typically used to assess the likely effects of site activities such as piling or heavy plant movements on neighbouring properties or structures.

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Geotechnical Desk Study and Site Investigation

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A desk study is an essential component of the geotechnical design process, providing a preliminary assessment of the site conditions. This involves a review of existing data and literature, including geological maps, soil surveys, and environmental reports. The desk study helps G&J's engineering geologists develop an initial understanding of the site (ground model), which is crucial for planning further investigations.

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A site investigation is a more detailed assessment of the site conditions, typically involving the use of intrusive techniques such as boreholes and trial pits to assess the ground conditions,  collect necessary of soil and rock samples, and often conduct in-situ tests. This investigation provides critical data for the refinement of the ground model, including site specific information on the soil and rock properties, leading to an appropriate geotechnical design.

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The desk study and site investigation are critical components of the geotechnical design process, providing a foundation for the development of buildable and cost-effective solutions. By undertaking a thorough desk study and site investigation, geotechnical engineers can identify potential geotechnical risks and develop strategies to mitigate them.