Project Sheet:
Pont Cwm Pydew Landslide

Client: Cyngor Sir Ddinbych / Denbighshire County Council

Contractor: Colin Jones (Rock Engineering) Ltd.

Construction Value: £128,500

Description of Project

Following a landslide in 2001, the B4391 road to the south of Bala was at risk of being undermined by future failures.

The road cuts though a steep valley side, and is supported locally by masonry retaining walls. Downslope of the landslide there is a hairpin bend, under which a culverted mountain stream flows. The bend collected water and was hazardous in freezing conditions.

In 2008 GroundSolve Ltd. were appointed to carry out an investigation of the landslide and design a cost effective, long term solution.

Rotary percussive probing was carried out using rope access techniques to define the rockhead profile along the failure. A soil nailed solution was then designed, with an anchored reinforced concrete beam at the crest of the slope to provide further protection to the carriageway.

In addition to the reinstatement works on the landslide, the following improvements were also incorporated into the works to minimise future maintenance and repairs:
·Reinforcement of failing masonry retaining walls with anchored, masonry clad reinforced concrete buttresses, see photo;
·Formation of a pre-cast drainage channel to collect groundwater which discharged from the upslope heathland;
·Repairs to the existing culvert headwalls

Site works commenced in April 2009, and were completed on schedule in August 2009.

Services inclusive of:
·ground investigation,
·detailed design,
·contract documentation and management
site supervision

Long reach excavator installing soil nails

Anchored reinforced concrete buttress (prior to cladding)

For all the project details please click on the PDF icon to download it.

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