Slope Stability Assessment
In areas of historical and active slope instability, slope stability assessments are often required prior to development and are sometimes required to satisfy conditions imposed by the local authority and/ or warranty provider.
Ruddlesden geotechnical has particular expertise in the area of slope stability assessments, including the stability of existing slopes that may be built on or cut into, as well as the assessment of slopes that have recently or historically failed (landslips/ landslides).
Slope stability assessments will almost always initially comprise a desk study, of historical, geological and other information, and walkover survey, followed by an intrusive (borehole and/ or trial pit) investigation, with laboratory testing and monitoring.
Slope stability analyses are undertaken using specialist computer software.
If necessary, slope stabilisation recommendations are provided, which might include safe slope angles, drainage, reinforcement (e.g. soil nails or retaining structures), earthworks or toe weighting.
Slope stability assessments are also often required for conveyancing purposes.
Slope Stability Assessment at Holiday Park, Dorset
It was proposed to locate several holiday lodges on the bank of a lake at a holiday park in Dorset.
Ruddlesden’s Phase 1 geotechnical assessment indicated that the bank was likely remnant from historical quarrying works and that it was likely to comprise re-worked natural soils (made ground).
As part of a geotechnical investigation of the site, slope stability modelling was undertaken to ascertain the effect the proposed lodges would have on the bank’s stability.
The stability modelling indicated that the placement of the lodges would likely lead to instability of the bank in the long term.
It was recommended that the lodges be relocated, their foundations be sited below the posturized slip-surface, the existing bank material be excavated and replaced with engineered fill, or the bank be retained, to mitigate the risk of landslip.