Project Sheet: Squires Gate, Higham Ferrers

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Client

  • Richards Moorehead and Laing Ltd

Works Undertaken

  • Ground investigation
  • Detailed design
  • Part time site supervision

Description of Project

Alongside a public highway in Squires Gate was an area of abandoned and flooded excavation that appeared to have once been a mineral working. The slope is separated from the road by a fence.

A vertical scar could be seen from the fence along the highway indicating a weakness in the slope, which was slipping down towards the flooded pit. At its maximum, the vertical face was about 1.5m high. It was thought that the carriageway above could be at risk. GroundSolve Ltd was approached to stabilise the slope.

After an initial ground investigation, it was decided that a stable zone adjacent to the carriageway was to be created. This was based on the assumption that after stabilisation, movement of soil further downslope may still continue (without compromising stability). This was chosen as stabilisation of the entire landslide was not affordable by the client.

The remedial works designed by GroundSolve Ltd involved the excavation of two terraces on the slope. This reduced the weight of the overlying soil, removing unnecessary load on the unstable slope. The terraces also provided a suitable surface for vehicular access to transport materials on site.

The terraces comprised augered holes that were drilled in order to installed timber piles that were grouted into place. Wire mesh and a geotextile separator were then placed between the timber piles to support the retained soil. However, to support the steps a contiguous bored pile wall was constructed.

Before construction: the scares visible on the slope (carriageway on the left). Immediately after completion
Before construction: the scares visible on the slope (carriageway on the left). Immediately after completion