ABSTRACT
In mountain tunneling, the bench cut method is used extensively due to its simplicity and flexibility to adapting to different ground conditions. And the method provides an advantage of simultaneous excavation of the upper and lower sections. The key issue of adopting this method is selecting a length and a shape of bench to assure the stability of the face, especially for tunneling in soft rock. In addition, auxiliary methods are used as required.When the ground is good enough, having enough self-supporting properties, the bench length can be reduced to 0 m (full face cut). In the case of a weak ground, the bench length is empirically decided. It is therefore important to evaluate and compare the effect of different bench length on the deformation of surrounding rock and on the stability of excavation front.
