Global and local stability analysis of slurry trenches under surcharge in soft soils

The global and local failure shapes and approaches for slurry trench stability analysis of diaphragm wall are studied by means of numerical simulation, centrifugal model tests, and theoretical analysis. From numerical simulation, the failure shape under surcharge in soft soil is approximately a pyramid for the slurry trench. Based on the limit equilibrium theory, the approach for global stability analysis of slurry trench is derived. On this basis, the global stability of a single soft soil layer in Ningbo, China, is analyzed, and engineering countermeasures are then put forward. Through centrifuge model test, the slurry trench is more prone to local failure in water-rich sand soils. On this basis, the approach for local stability analysis of slurry trench is derived for avoiding seepage failure.