Analysis on Reinforcement Effect of Tunnel Portal Longitudinally Traversing Landslide in Broken Rock Area

Influenced by the external environment and human factors, the tunnel portal landslide disaster is very easy to occur in the process of crossing the mountain. Taking the landslide at the entrance of Qingshashan left line tunnel as an example, this paper studies the deformation mechanism and reinforcement effect of landslide at the entrance by means of case statistical analysis, numerical simulation and field monitoring. It is shown that the landslide at the entrance of the tunnel belongs to the tunnel landslide parallel system, and the tunnel is below the sliding surface. The rock mass is disturbed, which results in the sliding deformation of the slope body after the excavation. Further, the tunnel structure appears crack because of the landslide thrust. The results indicate that construction disturbance and continuous rainfall are the main factors that may lead to slope sliding based on numerical analysis. The monitoring data show that the deformation and displacement rate of the landslide body is greatly reduced after the reinforcement measures', the stress state between the rock masses is constantly adjusted and gradually tends to a stable state, which basically achieves the expected treatment goal.