Landslide Tunnel And Anti-slide Piles Interaction Mechanism Study And Numerical Simulation

Tunnel is the common form for highway to cross a mountain slope when built in remote mountain areas. Slope and tunnel might produce disasters in different degree, seriously highway broken, when the landslide occurred. When manage these disasters by anti-slide pile, the distance between the anti-slide pile and the tunnel structure is one of the key factors of the success or failure of the treatment for the slide. If they are too close, the anti-slide pile will squeeze the tunnel, and make an increase of the landslide thrust acting on the tunnel structure. If they are too far, the soil between anti-slide pile and tunnel structure might form secondary landslide. Moreover, the reasonable distance is sensitive to the relative position of the slide surface and the tunnel. In order to solve this problem, in this paper, the function mechanism of landslide, tunnel and anti-slide pile were studied. At the same time, the sensitiveness of the reasonable distance with the relative location of tunnel and sliding surface varies was analyzed.In this paper, on the basis of predecessors’ research, the relative location of the tunnel and sliding surface is divided into three situations, the first is the tunnel intersects with the sliding surface; the second is the tunnel locates in the slip mass; the third is the tunnel locates in the bedrock. Corresponding to the three situations, three mechanical models of tunnel structure are extracted:the lateral shearing type, the smooth type and vault extrusion disturbance type. Combined with specific engineering example, the deformation characteristics of the tunnel in different mechanical models were analyzed, which provided theoretical basis for the back analysis to make a judgment of the certain location of sliding surface. On this basis, the three-dimensional finite element model was established. Through the calculation of two indicators of the slope safety factor and the deformation of tunnel lining structure, the sensitiveness of the reasonable distance with the relative location of tunnel and sliding surface varies was analyzed.According to analyze the computed results, mainly have the following conclusions:(1) The impact on the tunnel from the slide is the minimum within all models, when the tunnel is located in the bedrock. And the distance is the least sensitive to the relative position. Thus, the slide should be given priority to control and the tunnel deformation control should be complementary in the treatment to the disaster.(2) When the tunnel intersects with the sliding surface, the landslide has a bigger influence on the tunnel structure, and the tunnel structure bears the shear force action from slip mass and bedrocks. At the same time, the tunnel has certain resistance to the slide as a prolate hollow anti-slide pile. This should be taken in mind during the treatment. The distance is more sensitive to this kind of position, so in the treatment of the slide, we should take the reasonable distance through optimizing and comparing.(3) When the tunnel locates in the slip mass, the landslide has the biggest influence on the tunnel structure, even the tunnel may be broken. The distance is the most sensitive in this situation. If we make an improper selection, the soil between anti-slide pile and tunnel may form secondary landslide. So in the treatment, the pile and soil effects should be taken in mind to get a better treatment.In the last, the correctness of the numerical analysis and the feasibility of practical engineering were verified through specific engineering examples. And some engineering measures to aim at the tunnel deformation in landslide district were proposed, which can provide certain theoretical basis and reference opinions to the engineering management department for the similar engineering problems.