Project Sheet: Glaslyn Cottages

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Client

  • Gwynedd Consultancy

Works Undertaken

  • Survey of the existing wall
  • Site Investigation
  • Report providing geotechnical recommendations
  • Design of remedial work

Description of Project

The site is located on the western side of the A498 between Beddgelert and Tremadog. GroundSolve Ltd were commissioned to provide geotechnical recommendations for the strengthening of a retaining wall in front of a property in Snowdonia National Park.

The original retaining wall (known as the lower wall) supported two residential properties. The wall was showing signs of distress and there was evidence of water flowing through it. Another retaining wall, further upslope (upper wall) supported an oil tank, also needed strengthening.

GroundSolve Ltd. supervised the site investigation comprising hand dug trial pits and probe holes. The investigation confirmed the depth to rockhead which was important when considering the stability of the works in the temporary case and hence the options for the remedial works.

In order to minimise the extent of the excavation works and to protect the foundations of the cottages, the existing wall was taken down in lifts, while installing the soil nails / anchors.

The anchors were installed at 1m intervals down the face of the slope, and the face of the slope secured using a layer of mesh. The mesh and anchors were used to support both the excavation in the temporary situation, and the retaining wall in the permanent case.

The new stone wall was then built, and the area between the slope and wall was backfilled with layers of compacted site won material, imported granular material, and concrete.

The original stones were re-used for the facing of the retaining wall in keeping with the style of walls in the National Park.

Steps leading up to Number 2 Glaslyn cottage from the A498
Steps leading up to Number 2 Glaslyn cottage from the A498
The new wall under construction
The new wall under construction