Study on Large Deformation Rule of Soft Rock Tunnel Excavation in Intrusive Rock Alteration Zone
The section model of tunnel is established by using the discrete element method,and the influence rules of excavation penetration,step length,step height and crack density on the settlement and horizontal displacement deformation of tunnel vault are analyzed.The results show that the excavation footage has a significant effect on the settlement of the arch roof,and the reasonable range of excavation footage is 0.5～1m.When the ratio of step height to excavation height ranges from 0.3 to 0.4,the maximum arch settlement and horizontal convergence of surrounding rock tend to be stable,and the reasonable range of the ratio of step height to excavation height is 0.3 to 0.4.The increase of the arch settlement is about 7mm,the increase of the horizontal convergence is 18mm,and the effect of the fracture density on the horizontal dis-placement is more significant.
Tunnel engineeringIntrusive rock alteration zoneSimulation simulationSettling capacity
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