Collapsible Soil Evaluation in Liverpool

A five-storey residential block we recently assessed in the Kensington district showed clear signs of differential settlement after a wet winter. The underlying loess-like deposits in that part of Liverpool are prone to sudden volume loss when saturated under load. Our team carried out a detailed collapsible soil evaluation using double-oedometer tests and field density measurements to quantify the collapse potential. For shallow foundations on these materials, we always pair the assessment with a study of surface foundations to verify bearing capacity under wetting conditions.

Collapse strains above 2% under 200 kPa load require deep foundation solutions or Improvement before any structure can be built safely.

Process overview

Local context

Liverpool's industrial expansion in the 19th century saw extensive filling of the Toxteth and Edge Hill valleys with heterogeneous materials. These undocumented fills, combined with natural loessic silts from the Wirral Peninsula, create zones where collapse upon wetting is a real threat. We have documented cases where post-construction water leaks triggered 40 mm of differential settlement in buildings less than 15 years old. Our evaluation identifies these high-risk areas before excavation begins, allowing designers to specify appropriate Improvement or deep foundation systems.

Technical data

Relevant standards

BS 5930:2015 (Code of practice for ground investigations), Eurocode 7 (BS EN 1997-1:2004) – Design approach for collapse-prone soils, BS 1377-5 (Standard test method for measurement of collapse potential)

Common questions