Research on Deformation of Surrounding Rock and Bearing Force Characteristics of Supporting of Steeply Inclined Stratified Tunnel Under Ground Load

The surrounding rock of layered rock mass tunnel is prone to engineering problems such as bedding slip and bending deformation. Based on the project of Yujiang diversion tunnel in Guangxi, this paper studies the deformation characteristics of surrounding rock and the mechanical properties of supporting structure of shallow layered tunnel under surface load by using block discrete element method. The results show that under the condition of no support, the deformation of surrounding rock is small under the condition of no load and anti-dip lateral load, and the deformation of surrounding rock is significant under the condition of bedding lateral load. The deformation of surrounding rock is characterized by the bending and breaking of the anti-dip side wall, the sliding deformation of the vault and the bedding side wall. Under the supporting condition, the supporting force and deformation of the bedding side load are significantly greater than that of the bedding side without load. The axial force of the bedding side support is greater than that of the anti-dip side under the bias load of the bedding side, and the other three loads are opposite. The bending of the supporting arch waist is greatly affected by the load distribution. When there is no load and anti-dip side load, the anti-dip side arch waist bends inward and the bedding side arch waist bends outward, while the other two loads are opposite. The unilateral load mainly affects the deformation of the same side support, and the full load has the greatest influence on the deformation of the tunnel bottom.