Methods for Exclusion of Groundwater

This chapter provides an overview of the commonly used groundwater exclusion techniques, including the factors affecting the application of each technique. A wide range of exclusion techniques are available to form cut-off walls or barriers around civil engineering excavations. The method is mainly used when groundwater-induced instability is a major concern – either because ground conditions are favourable or because pre-drainage methods of groundwater control have been deployed to lower groundwater levels. A vibrated beam wall has little structural value, and the principal groundwater control applications have been to form deep temporary cut-off walls through easily penetrated ground conditions such as sands. Cross section through a slurry trench wall. The wall toes into a low permeability stratum to form a groundwater cut-off. The top of the wall is replaced by a cap of compacted clay to prevent drying and cracking of the hardened slurry.