Our Portsmouth laboratory provides essential soil classification and index testing aligned with BS 1377, critical for the city’s variable geology—from London Clay and Wittering Formation sands to harbour alluvium and made ground. Accurate particle size distribution via grain size analysis (sieve + hydrometer) quantifies silt and clay fractions that govern drainage and settlement behaviour. For cohesive strata, Atterberg limits determine plasticity indices and liquidity indices, directly informing foundation design and earthworks specification on the Solent corridor.
These tests support ground investigations for residential developments on former MOD land, coastal defence upgrades, and port infrastructure where soft clays and variable fills dominate. Contractors and consultants rely on this data for BRE 365 soakaway assessments, retaining wall design, and compaction verification. Complement classification with strength and chemical testing to fully characterise Portsmouth’s challenging ground conditions.
Geotechnical laboratory testing in Portsmouth provides the essential physical and chemical characterisation of soils and rocks to validate ground models and underpin safe, economical design. The local geology, dominated by the London Clay Formation, the Lambeth Group, and overlying Quaternary drift deposits including brickearth and river terrace gravels, demands careful assessment of engineering properties. Our facility supports the full lifecycle of a project, from routine classification through to advanced strength and compressibility testing, working strictly in accordance with the UK Specification for Ground Investigation, second edition, and BS 5930:2015+A1:2020. The data generated directly informs foundations design and complements field data from In-Situ.
All testing methodologies adhere to the rigorous standards mandated by UK practice, primarily BS 1377:1990 (Parts 1-9) for soils and BS EN ISO 17892 for geotechnical laboratory tests. Classification testing forms the core of any programme, encompassing moisture content, bulk and dry density, and particle size distribution. For fine-grained soils typical of the London Clay, grain size analysis using the hydrometer method is critical to determine clay fraction, which directly correlates with shrink-swell potential. This is further defined through Atterberg limits testing to establish the liquid limit, plastic limit, and plasticity index, key input parameters for assessing soil behaviour in Portsmouth's variable ground conditions.
Portsmouth's engineering landscape, from the redevelopment of brownfield sites in Tipner and the city centre to coastal defence works and infrastructure upgrades along the M27 corridor, presents specific geotechnical challenges. The presence of soft alluvium, compressible clays, and made ground requires a robust laboratory programme to mitigate risks of differential settlement and slope instability. Testing for schemes involving large earthworks or deep basements frequently requires shear strength determination in the triaxial cell or direct shear box, while one-dimensional oedometer consolidation tests quantify the settlement characteristics of clay strata under load. These advanced tests are often scheduled alongside field investigations like the Cone Penetration Test to create a high-resolution ground profile.
The process begins with sample receipt and storage in our humidity and temperature-controlled environment to preserve sample integrity, as specified in BS EN ISO 22475-1. Clients receive a clear schedule of proposed tests, and upon completion, a comprehensive factual report presenting all results, graphical plots, and test condition observations. The value lies in delivering defensible, repeatable data that reduces ground uncertainty, allowing engineers to optimise foundations and earthworks design. For projects requiring verification of engineered fill, our team also performs field density testing using the sand cone method to correlate laboratory compaction curves with site performance.