Landfill Geotechnics in Liverpool

Liverpool sits on Triassic sandstone and glacial till, with a water table as shallow as 2 m in parts of the city. That combination makes landfill geotechnics a specialist discipline here. We have worked on closed municipal sites in Speke and brownfield redevelopment zones where waste thickness exceeds 12 m. Before any capping or foundation design, we evaluate the waste mass using boreholes and CPT testing to map refuse composition and void ratio. The same dataset feeds into settlement modelling and gas generation forecasts.

A 2 m water table and 12 m of waste make settlement prediction the critical path in Liverpool’s landfill geotechnics.

Process overview

Local context

Liverpool’s 800 mm annual rainfall and clay-rich glacial tills create a high risk of leachate mounding within the waste mass. During heavy winter storms, perched water tables can rise 1.5 m in 48 hours, reducing effective stress and triggering instability in steep side slopes. We mitigate this through drainage layers designed with factor of safety ≥ 1.5 under saturated conditions. Gas migration is another hazard — methane concentrations in the unsaturated zone can exceed 5 % LEL if the cap is not properly sealed. Our monitoring arrays include piezometers and gas wells installed at 20 m centres.

Technical data

Relevant standards

BS 5930:2015 – Code of practice for ground investigations, BS EN 1997-1:2004 (Eurocode 7) – Geotechnical design, Environment Agency LFTGN 04 – Landfill gas monitoring guidance

Common questions