The site investigation was carried out by Solmek on a large area of redevelopment land in the Redheugh area of Gateshead, commonly known as Clasper Village, Tyne and Wear. The proposed development comprises c.180no residential houses with front and rear gardens along with hardstanding as access roads and parking.
Solmek were initially tasked with undertaking the initial Phase 1 Desk Study and Coal Mining Risk Assessment for the scheme. This was followed with a series of site investigations to prove the underlying ground conditions and provide samples for geotechnical and contamination laboratory design. Additionally, the site contained four known former mine entries and the Coal Authority requested each of these were found by intrusive methods.
Fieldwork was undertaken as:
• A series of small percussive boreholes drilled to depths of between 0.90 and 5.45m below ground level (bgl). – The borehole locations were spread across the whole area to give a general site coverage to determine shallow ground conditions and obtain samples for geotechnical testing and environmental samples for contamination testing.
• Installation of combined ground gas and water wells. – Installations placed around the site (25-50m distance) to capture potential ground gas from the areas of made ground.
• A number of cable percussive boreholes drilled to depths of between 13.95mbgl and 19.95mbgl. – The borehole locations were spread across the whole area to give a general site coverage. – Boreholes drilled to determine deeper ground conditions and obtain samples for geotechnical testing and environmental samples for contamination testing.
• A series of dynamic probing to depths of between 5.00 and 6.00mbgl. – The aim of the probes was to attempt to locate the up and down shafts of Redheugh Colliery
• 2no days of hand-held rotary probing to depths of up to 20.00mbgl. – The aim of the probes was to locate the up and down shafts of Redheugh Colliery based on
• Hand-held rotary probing to depths of up to 20.00mbgl.
– The aim of the probes was to locate the up and down shafts of Redheugh Colliery based on Numerous machine excavated trial pits to depths of between 0.60 and 4.00mbgl.
– The trial pits were excavated to obtain details of the shallow soil profile and obtain samples for geotechnical testing and environmental samples for contamination testing.
– Specific trial pits undertaken to prove the location of mine shafts at the site.
In-situ standard penetration tests (SPT) were undertaken in the boreholes. Undisturbed samples were undertaken within the cable percussive boreholes. Insitu hand shear vane tests were carried out in the trial pits and small percussive boreholes along with taking disturbed samples and environmental samples for laboratory testing.
Solmek successfully located all four of the shafts which enabled the client to position the proposed housing in areas to avoid the influence of the shafts. The client has also been able to obtain costs to cap and grout the shafts.