Research On The Interaction Between Tunnel Structure And Landslide With Large Intersection Angle

The geographic conditions and geologic structure in the west area are complex.We must construct highway tunnel and railway tunnel in the bad geological areas such as landslide if we can not leave.But the constructed mountain-adjacent tunnel becomes disease with the mountain deformation.This is called landslide-tunnel.At present,the studying on the landslide-tunnel is concentrated on the situations that the relation between the tunnel axis and landslide trend is vertical or parallel. Aiming at the present research status,this paper has researched on the situation that the angle between tunnel axis and landslide trend is large.This paper has studied interaction mechanism between rock and tunnel and discussed the the distribution of the landslide thrust on the tunnel and the deformation law of the tunnl by formula derivation and numerical simulation.According to the concrete analysis,we find the optimal value of the angle of the anchor cable.The main research resultscomes follow:(1)Because the interaction mechanism between rock and lining is different,there are different types of the landslide-tunnel.So this paper classifies the types of landslide-tunnel at first:①According to the angle between the landslide trend and tunnel axis,there are3types: parallel,vertical and skew.②According to the relative relation between the tunnel and slip surface, there are3types:the tunnel is in the landslide bed,crossing the slip surface and in the sliding mass.③According to the number of the slip surface,there are single sliding face and several slip surfaces.(2)This paper illustrates5causes of the landslideand and4factors which affect the deformation and cracking of the tunnel.Based on this,we conclude4geological mechanics models and analyses the deformation features of the4kinds.(3)This paper analyses tunnel axis which is vertical with the landslide trend and is parallel with the landslide trend.We come the conclusion of the interaction mechanism between rock and lining and the failure modes and bring the landslide-tunnel in the paper forward..We can decompose the landslide thrust to the direction which is parallel with the tunnel axis or vertical with the tunnel axis.By introducing the space distribution function of the landslide thrust,the paper put forward a method of calculating the landslide thrust in space.Then we discusee the distribution of the landslide thrust,the internal force of tunnel lining and the tension of the anchor cable.We conclude that the deformation has3kinds:bend, tension and compression in axis and shear deformation.(4)Taking the BeiEr tuunel as the example,apply the theory on engineering practice,the paper illustrates the method of this theory and comes to a conclusion that the section which is the abruptest and with thickest overburden is the main section.The landslide thrust on the lining is near the tunnel exit and decreases.(5)The paper use ABAQUS to simulate the BeiEr tunnel.The section of the tunnel has8monitor points. We analyse the deformation rule along the axis and sideslip of these8points and the affection factors of the governance that which is the best angle between the anchor cable and the cross section or horizontal plane of the tunnel. At last,we compare the result of the numerical simulation to theory to prove it success.