Geotechnical disputes involving soil types and their behaviour

Understanding the soil beneath a structure is essential when assessing foundation performance, ground movement and the cause of building damage. Clay, sand, silt, gravel and organic soils each respond differently to loading and changes in moisture, as illustrated in the accompanying graphic.

Clay may expand and shrink as its moisture content changes, while sand generally drains more freely. Silt can lose strength when wet, gravel usually provides good drainage and bearing capacity, and organic soils can compress considerably under load. These descriptions provide a useful overview, although actual ground behaviour depends on factors including soil density, composition, groundwater conditions and the design of the foundations.

Disputes can arise when ground conditions have been incorrectly identified, inadequately investigated or not properly considered during design and construction. Wilgeo provides independent expert witness advice on soil behaviour, foundation performance, settlement and other geotechnical matters, supported by an assessment of the available site investigation, design and construction evidence.