Effects of different bench length on the deformation of surroundingrock by FEM

摘要

Bench cut method has been extensively used in mountain tunneling. This is mainly due toits flexibility to adapting to different ground conditions. Induced displacements are empirically controlled byadjusting the speed of excavation, the bench length, partial-face excavation and closure of invert. In this paper,a series of three-dimensional, numerical, elastoplastic analyses were conducted to investigate the effects ofdifferent bench length on the deformation of surrounding mass in soft rock. The closure of invert was alsoinvestigated to their role in controlling the final displacement. When bench cut method adopted in soft rock, thebench length should not be too long or too short and 0.5 times of tunnel diameter around for bench length isappropriate.