In Swansea, comprehensive roadway investigation must address the region’s complex geology, ranging from the Coal Measures and glacial till deposits in the valleys to estuarine alluvium and soft marine clays along the Tawe corridor. A robust ground investigation is not merely preliminary; it is a fundamental requirement under UK-specific standards to mitigate risks associated with historic mining voids, compressible soils, and variable groundwater conditions. Our approach integrates a full suite of services, from initial ground investigation to advanced Cone Penetration Testing (CPT), ensuring that every pavement design accounts for the specific geotechnical constraints of the site, fully compliant with the Specification for Highways Works and Eurocode 7.
The technical methodology for roadway schemes relies on a combination of intrusive and geophysical techniques, executed in accordance with BS 5930:2015+A1:2020 and the Design Manual for Roads and Bridges (DMRB). We deploy high-resolution CPT testing to derive near-continuous profiles of tip resistance and sleeve friction, which is particularly effective for profiling the soft, normally consolidated clays found in Swansea’s coastal and estuarine zones. This data is verified and supplemented by high-quality sampling from boreholes, enabling precise laboratory testing to determine effective stress parameters. For granular sub-base and capping layers, our sand cone density testing provides essential field verification of compaction levels, ensuring compliance with the Series 600 Earthworks specification.
Typical roadway projects in Swansea present distinct geotechnical challenges that demand a targeted investigation strategy. Highway improvement schemes along Fabian Way or widening projects near the River Tawe must contend with deep deposits of soft alluvium, requiring rigorous Atterberg limits testing to accurately predict settlement and lateral spreading potential. In contrast, residential and commercial access roads on the slopes of Townhill or Morriston often encounter weathered glacial till with high boulder content, where a combination of dynamic probing and trial pitting becomes essential to assess rippability and foundation conditions. For these slope-stability-sensitive sites, particle size distribution analysis by both sieve and hydrometer is critical for designing drainage and reinforcing elements within the pavement structure.
The investigative process is managed from initial desktop study and utility clearance through to a fully interpretative report, delivering actionable data for pavement engineers. The final deliverable includes a comprehensive Ground Investigation Report with detailed factual logs, laboratory test results, and geotechnical design parameters, including CBR values and modulus of subgrade reaction. By correlating in-situ field and lab testing, we eliminate over-conservative designs and reduce the risk of costly construction delays. This integrated, compliance-driven approach ensures that foundation and pavement designs for Swansea’s roadways are optimised for long-term durability and performance, regardless of the challenging local ground conditions.