Study On Stability And Treatment Design Of YangShengGou Tunnel-Landslide System

In this paper,YangShengGou landslide and proposed tunnel are taken as research subjects,through field geological survey,field exploration and laboratory test,the formation mechanism and development history of landslide are discussed,the interaction between tunnel and landslide under parallel system is studied,and the stability of landslide is evaluated by limit equilibrium method and strength reduction method.In order to intuitively analyze the stability change,stress,strain,displacement of landslide and the deformation of tunnel under the action of landslide thrust,Midas GTS/NX software is used to simulate the real situation.Finally,according to the calculation results of landslide stability,combined with the actual situation and relevant engineering experience,reasonable treatment scheme and suggestions are put forward.The main contents and achievements of this paper are as follows:(1)According to the location relationship,the YangShengGou landslide and the proposed tunnel belong to the tunnel-landslide parallel system,in which the stability of landslide is changed due to the excavation of the tunnel entrance,and the deformation of the tunnel is mainly due to the thrust of the landslide.(2)Through field investigation,laboratory test and limit equilibrium analysis,we can see that YangShengGou landslide is a slumpingslide,deepslide,giant landslide,loess-mudstone landslide and fossil landslide.The plane shape of landslide is irregular,the upper part of landslide is thin and the lower part is thick,and the overall potential energy is low.Section I-I and section III-III are not affected by engineering excavation and have good stability under different conditions.The stability of II-II section is good under normal conditions,but it tends to be unstable gradually with rainfall and earthquake action,and the stability of section becomes worse after excavation.(3)Using Midas GTS/NX to simulate the landslide,and the results show that the most dangerous sliding surface and its stability coefficient obtained by simulation are consistent with the limit equilibrium method,and under different working conditions,the distribution of stress,strain and displacement in landslide is the same.With rainfall and earthquake,the values of stress,strain and displacement increase and the stability of landslide decreases.(4)Using Midas GTS/NX to simulate the tunnel,the results show that the stress of tunnel lining is different in different locations.From sliding zone to tunnel entrance,the axial force of tunnel develops from tension + shear to compression + shear e,and then to tension + shear at tunnel entrance.The maximum displacement occurs at the sliding body position.(5)According to the actual situation of the landslide and the proposed project,we put forward the landslide control measures and tunnel reinforcement suggestions,which not only ensure the overall stability of the landslide,but also greatly reduce the landslide thrust acting on the tunnel lining.Finally,use numerical simulation to verify the rationality of the treatment scheme.