Ground investigation in Coventry demands a thorough understanding of the region's complex glacial and post-glacial geology, primarily characterised by Quaternary drift deposits overlying the Triassic Mercia Mudstone Group. A compliant ground investigation must be designed to the rigorous standards of BS 5930:2015+A1:2020, the code of practice for site investigations, to de-risk projects from initial feasibility through to construction. The variable drift, ranging from cohesive glacial till (boulder clay) to granular glaciofluvial sands and gravels, often masks unpredictable bedrock weathering profiles and the presence of soft alluvium in the River Sherbourne and Sowe valleys, making a tailored, phased approach essential for accurate soil classification and geotechnical characterisation.
Our investigative methodology integrates a phased suite of intrusive techniques to build a robust ground model. We commence with cable percussive boreholes to facilitate Standard Penetration Testing (SPT) and retrieve high-quality undisturbed samples using Shelby tubes, specifically targeting the cohesive tills and Mercia Mudstone for accurate strength and stiffness profiling. This is systematically combined with Cone Penetration Testing (CPT) to provide a near-continuous stratigraphic record, precisely identifying thin granular layers or soft zones susceptible to settlement. The in-situ strength of sensitive clays is further verified using the field vane shear test (VST), ensuring undrained shear strength parameters are directly measured without the disturbance inherent in sampling, all in strict accordance with the relevant parts of BS EN ISO 22476.
This multi-faceted investigation strategy is critical for the diverse developments shaping Coventry, from the regeneration of the city centre and Friargate business district to major logistics parks on the urban fringe. For a typical industrial shed on the Coventry clay, the integration of CPT and SPT data provides a high-resolution profile to optimise pad foundation design, while the precise classification of granular deposits is vital for assessing sulphate and sulfide attack potential on buried concrete per BRE Special Digest 1. On brownfield sites, our phased In-Situ approach is indispensable for validating remedial strategies, correlating penetration resistance with contamination delineation, and generating design parameters for earthworks without exposing personnel to potential hazards unnecessarily.
From the initial utility clearance and safe execution of fieldwork to the delivery of a comprehensive, interpretative report, our process is direct and client-focused. The final report moves beyond mere factual data, presenting a clear geotechnical model complete with characteristic values derived for the limit state design of foundations and retaining walls in compliance with Eurocode 7. By combining accredited laboratory testing with precise field data, we provide engineers and developers in Coventry with a single, definitive document that directly informs structural design, minimises costly over-design, and manages residual ground risk with clarity and authority.