​Common causes of slope failure include an increase in the load applied to its crest (for example the stockpiling of soil, the building of structures such as houses with poorly design foundations, or even over time, the growth of trees), a decrease in the soils shear strength (for example softening due to weathering or changes in porewater pressure), steepening of the slope profile (often by human activity), or removal of the slope's toe (often by human activity or river erosion) of the removal of other toe loads such as buildings or retaining structures.

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Whether you have land with an existing slope that has the potential to fail, is in the process of failing or has already failed, or are proposing earthworks that will create new slopes, G&J can help. Following an initial site visit, together with some background research (a targeted desktop study looking at things like likely geology, site history, groundwater depths and topography), we can make recommendations for a cost-effective way forward with regard to any necessary topographical surveys, ground investigation and testing, monitoring and remedial/stabilisation works.​

 

The precise nature of a ground investigation will depend on the findings of the desktop study together with factors such as the extent and height of the slope, its gradient, and access restrictions (for example can we access the top of the slope but not the bottom). The investigation may involve the drilling of boreholes and/or the excavation of trial pits; the latter often giving a clearer view of the ground conditions but with depth limitations. ​Once any necessary ground investigation works have been planned and carried out, which may include the placement of monitoring installations such as inclinometers and piezometers, G&J can carry out any monitoring (in-house) to help determine any on-going movement rates and direction, the depth that any active movement is taking place, and any changes of water level or porewater pressure over time due to factors such as heavy rainfall which may accelerate on-going slope failure or increase the risk of failures starting.​

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G&J's experienced engineering geologists will then create ground models of the slope and the area around it, based on factors including the observed geology (e.g. borehole data), geotechnical test results, any loads (such as mounds of soil or buildings on top of the slope), groundwater conditions, and topography. These models can then be used, together with commercially available software to undertake slope stability assessments to better inform the levels of risk and help target any necessary remedial works.

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G&J has recently undertaken slope stability assessments ranging from on-going slope failures affecting residential properties in Gloucestershire to the assessment of proposed slopes associated with earthworks schemes at development sites throughout the Midlands.