White Hart, Machen, Caerphilly, Wales

The demolition of the existing derelict Public House (White Hart Inn) and the construction of eight 3-storey houses

Client: Private developer

Site Investigation Value: £2,500

Project Overview

This development comprised the demolition of the existing derelict Public House (White Hart Inn) and the construction of eight 3-storey houses with areas of proposed hardstanding comprising parking bays, patios and domestic gardens.

Site Investigation Overview:

The works comprised an intrusive ground investigation at the site to establish the ground conditions and suitability of the natural geological strata for the proposed development. As part of the site works and due to the potential for slope movements in the area, an additional study of historic maps and Site Reconnaissance was commissioned by the client, as recommended by Soils Limited.

What did Soils Limited bring to the table

The scope of the investigation comprised:
 3No. windowless sampler boreholes;
 3No. dynamic probes;
 Geotechnical laboratory testing.

The intrusive investigation revealed that the site was situated on “Made Ground” of extensive thickness reaching 2.70m in places. A number of potential scenarios were considered regarding its possible origin:

 Landslide debris considering the site’s location, situated on a steep hill (circa 16% slope grade);
 Fill depositions due to an adjoining railway embankment;
 Cut-and-fill operations to provide a level base for the construction of the existing building;
 Mine waste considering the wider area’s history as it had been previously extensively used for mining/quarrying.

It was apparent that a piled foundation scheme would be the most suitable foundation solution as the excessive thickness of “Made Ground” elsewhere on site could not be ruled out along with the possibility of landslide debris.

In order to provide the Client with a viable alternative, Soils Limited recommended a Site Reconnaissance to be undertaken by Prof E. N. Bromhead, a consultant to Soils Limited and an international authority on the stability of slopes. This proved to be a turning point for the project as following a Site Reconnaissance by Prof E. N. Bromhead it was concluded that there were no indications of landslide phenomena previously occurring either on-site or in the immediate vicinity. This, therefore, dramatically minimised costs and timings, meaning that the next stage of the project could commence.

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