In Wigan, a robust ground investigation is the essential first step for any construction or civil engineering project, ensuring safety, stability, and compliance with UK standards. The local geology, dominated by the Pennine Coal Measures with layers of sandstone, mudstone, and historic shallow mine workings, presents specific challenges that demand thorough assessment. Our investigation services directly address these, identifying potential hazards like made ground, abandoned shafts, and variable bearing capacities. This process is guided by CD 622 (Managing Geotechnical Risk) and the recommendations of British Geological Survey (BGS) mapping, forming the basis of a safe and cost-effective design from the outset.
Our methodology strictly adheres to the UK specification for ground investigation, primarily the second generation Eurocode 7 (BS EN 1997-2:2024) and the Institution of Civil Engineers (ICE) UK Specification for Ground Investigation. A phased approach typically begins with a desktop study and walkover survey, followed by intrusive works. Core techniques include the CPT (Cone Penetration Test), which provides continuous profiles of soil behaviour, and rotary drilling to recover high-quality samples for detailed logging and laboratory testing. These are supplemented by In-Situ such as Standard Penetration Tests (SPT) and permeability assessments to determine engineering parameters directly within the ground.
Wigan’s post-industrial landscape means projects often involve the redevelopment of brownfield sites for residential or commercial use. For these, accurately determining the fill’s compaction is critical, which we achieve through the field density test (sand cone method) to verify engineered backfill and provide confidence for foundation design. Our accredited laboratory then undertakes a suite of tests to classify the recovered materials and define their mechanical properties. This includes fundamental index testing such as grain size analysis (sieve + hydrometer) for particle size distribution and Atterberg limits to assess the plasticity of fine-grained soils, which is vital for predicting shrink-swell potential in cohesive strata common across the region.
Our investigation process delivers a clear, actionable ground model, transitioning from site works to a comprehensive interpretative report. This final deliverable presents a detailed assessment of ground conditions, geotechnical parameters, and potential constraints, providing clear recommendations for foundations and earthworks. We distil complex data into a practical document that empowers architects, structural engineers, and contractors to make informed decisions, reducing the risk of unforeseen ground conditions. The ultimate value is a de-risked project, optimised foundation solutions that avoid costly over-design, and demonstrable compliance with building control requirements, ensuring your Wigan development proceeds with certainty.