Analysis of the corner effect on excavation behaviors

This paper presents three-dimensional finite-element studies on excavation problems. Large computer storage and computation time are normally required for the conventional finite-element analysis, for which the boundary should be located distant from the excavation zone so that convergence can be reached. In this paper the infinite element is incorporated into a three-dimensional finite-element computer program for minimizing the number of elements used. Research results indicate that adequate convergence for the wall deflection and ground surface settlement is obtained for infinite elements located at a distance of one wall depth. This substantially reduces the number of elements used in the analysis. Furthermore, two excavation case histories are provided to confirm the appropriateness of employing the infinite element as well as the corner effect on the deformation behavior. Based on the field observations and three-dimensional analysis of the case histories, it is found that the wall deformation at the short wall is smaller than that at the long wall. The wall deformation decreases with decreasing distance from the corner. These studies further verify the corner effect on the excavation behavior.Key words: Corner effect, Finite-element method, Deep excavation, Infinite element