A design method for slurry trench wall stability in sandy ground based on the elasto-plastic FEM

Deep-trench excavation supported by slurry has become a widely used technique for the construction of diaphragm walls. It has been proved by numbers of field tests, scale model tests and numerical analyses that the supporting effect of the slurry in the trench will provide sufficient stability for the deep-trench excavations. However, there is still neither a generally accepted theory of the failure mechanisms of the slurry trench, nor a widely used design method. This paper gives suggestions for the practical design on the stability of the slurry trench based on the elasto-plastic finite-element method (FEM) analysis, which consists of two parts. The first part is concerned with the evaluation of slurry trench stability in terms of safety factor. The safety factor was calculated using the shear strength reduction technique in the FEM and verified by comparison with centrifuge tests. The second part suggests a method for choosing the preliminary slurry parameters, i.e, the height of slurry filling and slurry density, based on the active earth pressure FEM. (C) 2000 Published by Elsevier Science Ltd. All rights reserved.