Mindlin solution on ground deformation caused by the trench excavation during installation of concrete diaphragm wall panels

Abstract

Concrete diaphragm walls (CDWs) are widely used as support of deep excavation in soft ground in urban areas. Ground deformation occurs during the excavation of trenches for the installation of the CDW panels due to ground stress release. This paper investigates the ground deformation during slurry trenching using Mindlin solution. The pressure of slurry used to protect the trench stability during excavation is simulated as a triangularly distributed load on the trench walls, the soil stress state is solved using Mindlin solution, and the horizontal and vertical ground displacement are obtained through integral transformation of ground strain. The rationality of the solution is verified through comparison between the analytical solution and field measurement. Sensitivity analyses are performed on soil elastic modulus, Poisson's ratio, trench excavation depth and panel length. Simplified formulation is proposed for the prediction of horizontal ground deformation. The impact of excavation stages and adjacent panels on the ground deformation is explored. The study finds that the Mindlin solution is able to provide an approximate solution on the ground deformation during slurry trenching, and the simplified formulation can be used to provide a fast estimate of the horizontal ground movement in engineering practice.