Abstract: In this paper, roadways with different cross-section shapes, including rectangular, trapezoidal, straight wall arch, horseshoe-shaped, oval and round shape, are selected to be optimized. Based on FLAC3D simulation, the surrounding rock deformation characteristics and rock plastic zone distribution are studied after the excavation of six kinds of typical roadway, and the influence of different side pressure coefficient to them is also analyzed. The numerical simulation results show that the cross-section shape has large effect on the deformation characteristics and plastic zone distribution of surrounding rock. According to the size of side pressure coefficient and direction of principal stress, the round and oval shapes are the optimal cross-section shapes of deep roadway under high ground stress. Thus, selecting the roadways with round and oval shapes, can improve the stress state of surrounding rock, reduce the deformation amount and damage range of plastic zone in surrounding rock, which is beneficial to the long-term stability of deep soft rock roadway under high stress.

Key words: deep level, soft rock roadway under high stress, cross-section shape of roadway, FLAC3D numerical simulation