Together, we solve the challenges of tomorrow.
SEE MORE →In-situ testing forms the cornerstone of reliable geotechnical investigation across Bognor Regis, encompassing a suite of field-based methods that assess soil and material properties directly within their natural setting. Unlike laboratory tests that rely on extracted samples, these procedures measure density, strength, permeability and deformation characteristics without disturbing the ground's original structure, delivering data that truly reflects site conditions. For a coastal town built upon complex superficial deposits and shaped by maritime influences, the accuracy of in-situ evaluation directly determines the safety of foundations, the stability of earthworks and the longevity of infrastructure investments.
Bognor Regis sits upon a geological framework dominated by Quaternary Brickearth and Head deposits overlying the Cretaceous Upper Chalk Formation. The Brickearth—a silty, loess-like material—can exhibit collapse potential when wetted, while the underlying Chalk presents variable weathering grades and solution features that create sudden changes in bearing capacity. These conditions demand rigorous field verification, as traditional borehole sampling often fails to capture the true heterogeneity of these strata. The town's low-lying topography and proximity to the English Channel further introduce groundwater sensitivity and potential for saline intrusion, making in-situ permeability and density assessments critical for any development touching the water table.
All in-situ testing conducted in Bognor Regis must comply with the UK Specification for Ground Investigation, second edition (ICE, 2012), alongside BS 5930:2015+A1:2020 (Code of practice for ground investigations) and BS 1377 (Methods of test for soils for civil engineering purposes). These standards prescribe equipment calibration, test procedures and reporting formats that ensure results are defensible under scrutiny from building control bodies, warranty providers and the Environment Agency. For projects involving the Chalk, reference to CIRIA C574 (Engineering in chalk) provides essential guidance on interpreting field data within this problematic geology.
The range of projects requiring in-situ testing across Bognor Regis is extensive. Residential developments on former greenfield sites routinely need field density tests using the sand cone method to verify engineered fill compaction beneath foundations and floor slabs. Coastal defence schemes demand plate load tests and dynamic probing to assess the integrity of shingle banks and underlying strata before rock armour placement. Commercial builds on the town's regeneration zones require precise bearing capacity verification through standard penetration testing (SPT) and cone penetration testing (CPT), while highway improvements along the A259 corridor depend on in-situ CBR values to design flexible pavements capable of withstanding tidal groundwater fluctuations.
In-situ testing measures soil properties in their natural state without disturbing the ground structure, capturing true field conditions such as moisture content, stress history and fabric. Laboratory tests analyse disturbed or undisturbed samples under controlled conditions. For Bognor Regis's variable Brickearth and Chalk, in-situ methods often provide more representative strength and density values, while laboratory tests allow classification and chemical analysis. A comprehensive investigation typically combines both approaches.
In-situ density tests are mandatory whenever engineered fill is placed, including beneath foundations, floor slabs, road subgrades and behind retaining walls. They verify that compaction meets the specified relative density or air voids requirement. In Bognor Regis, where made ground and reworked Brickearth are common, density testing ensures fill achieves the design bearing capacity and minimises future settlement. Building control and warranty providers such as NHBC routinely require these test records.
Investigation depth varies significantly by method. Dynamic probing and standard penetration testing can reach depths exceeding 20 metres, depending on soil resistance. Cone penetration testing typically achieves 15 to 30 metres in suitable soils, though the Chalk's variable hardness may limit penetration. Plate load tests and density tests assess near-surface conditions, usually within the top metre. The chosen depth depends on the project's zone of influence, such as foundation depth plus the bulb of pressure.
BS 5930:2015+A1:2020 provides the overarching code for ground investigation practice, including in-situ test selection and execution. BS 1377 Parts 1 to 9 detail specific test methods for soils, covering density, penetration resistance and permeability. The ICE Specification for Ground Investigation sets contractual and technical requirements. For Chalk-specific interpretation, CIRIA C574 offers supplementary guidance. Compliance with these standards is essential for regulatory approval and technical credibility across all Bognor Regis developments.
We serve projects across Bognor Regis and surrounding areas.