South Road Retaining Wall, Weston-super-Mare. Ground Investigation Works

The Proposed Ground Investigation works contract comprises the following works:

• 5 No. boreholes advanced using a drilling rig capable of both dynamic sampling and rotary coring that can obtain the required samples through possibly made ground/fill, superficial deposits and solid geology to a depth of 7 mbgl. Collection UT100 undisturbed samples where possible/appropriate, SPT testing and collection of rock cores. Boreholes shall be a minimum of 1.5m back from the retaining wall.
• 5 no. hand dug observation pits of the retaining wall foundations.
• 3 no. horizontal diamond core holes through the retaining wall to confirm wall thickness and the nature of the materials directly behind the wall.
• Soils to be logged in accordance with BS EN ISO 14688-1:2002+A1:2013 and BS 5930:2015.
• Rock to be logged in accordance with BS EN ISO 14689-1:2002, BS 5930:2015.
• Geotechnical laboratory testing on selected samples.
• Environmental testing on selected samples.
• Provision of AGS data.
• Ground Investigation Factual Report (as per 16.8.1)

Specific borehole requirements are detailed further in Schedule 1 and Schedule 2 of Ground Investigation (GI) Specification. The proposed borehole location plan is attached to the GI.