Research on Permeability Characteristics of Waterproof Curtain Slurry for Foundation pit in Saturated Sand

For the construction of a waterproof curtain in saturated and highly permeable sand, conventional slurry often fails to form a filter cake and instead penetrates through the sand, leading to a loss of impermeability at the working face and posing a risk of instability. This study, based on a self-designed 3D variable cross-section slurry permeation column test system, aims to investigate the mechanism of filter cake formation during slurry permeation. The results reveal distinct permeation patterns in the sand as the viscosity coefficient of the slurry increases, including the permeation zone type, filter cake - permeation zone type, and filter cake type. Low-viscosity slurry samples fail to develop a filter cake, resulting in the majority of slurry pressure acting on the sand layer, which is detrimental to both seepage prevention and face support. Conversely, high-viscosity slurry samples form a dense filter cake. The increase in slurry viscosity promotes stronger interactions between slurry particles and sand particles, leading to the formation of a denser filter cake with accelerated development. The increase in slurry viscosity promotes stronger interactions between slurry particles and sand particles, leading to the formation of a denser filter cake with accelerated development.