Numerical analysis for backside ground deformation behaviour due to braced excavation

Abstract

Beam-spring model analysis is usually used as a practical design method for braced excavation in Japan. This method, however, has some limitations in large scale braced excavation, for example, sometimes observed wall displacement exceeds the design value in very soft and thick clay layer. In order to predict the influence of excavation process on ground deformation, it is necessary to employ numerical methods such as finite element method in which the interaction effects of soil and braced wall are taken into consideration. In this research 2D finite element analyses have been carried out for simulating a real field monitoring data of braced excavation. The observed data, design value computed from beam-spring model and the results of 2D FE analysis using an elasto-plastic constitutive model of soil (subloading tijmodel) are compared and evaluated in this paper. It is revealed that the analyses can properly capture wall displacement, surface settlement and deformation mechanism of the ground.