Client: Perfect Circle JV on behalf of the Internal Drainage Board Contract
Value: Circa £205k
Role: Principal Contractor
This project involved the construction of two flood banks and two pumping stations south of Kessingland, Suffolk. The ground investigation provided essential geotechnical and geoenvironmental data to support the design of the flood banks, new river channel, pumping stations, and potential borrow areas for bund fill materials.
Challenges and Site Conditions:
The works were located within the floodplain of the Hundred River, with extensive soft soils including peat and alluvium. Ground conditions were highly variable and groundwater was encountered near the surface, presenting challenges for access and plant stability.
Our Approach
- Deployed tracked dumpers and low-ground-pressure balloon tyres to mobilise drilling rigs and plant across soft ground to drill 14 no cable percussive boreholes to depths ranging between 20 m and 25 m.
- Utilised tracked plant for trial pitting and crawler-mounted CPT rigs for cone penetration testing to 20 m at 36 no locations across the site.
- Drilled windowless sampled BH’s to 5 m depth and dynamic probe (super heavy) to 20 m in areas inaccessible with a cable percussive drilling rig
- Implemented piston sampling techniques to obtain high-quality undisturbed samples from soft soils.
- Provided UKAS accredited geotechnical and contamination laboratory testing services on appropriate recovered soil and groundwater samples.
- Conducted staged monitoring of groundwater levels to inform the flood defence design.
Outcome
Despite access constraints and soft, waterlogged terrain, all phases were completed safely and to programme. The data provided enabled detailed design of the flood banks and informed borrow area suitability assessments.
