| With the rapid development of China’s economy,the construction of roads,railways,and other infrastructure is rapidly extending to the central and western regions.Since the central and western regions are mountainous areas,roads,railways,and other infrastructure are usually tunnel through the mountains.Due to the requirement of line ride comfort or the limitation of topographic and geological conditions,more and more tunnel construction passes through the landslide.Tunnel excavation will cause some disturbance to the landslide body,which will cause landslide collapse in serious cases,and the sliding body will also have an important impact on the stability of the tunnel structure.Therefore,it is of great significance to study the influence of tunnel underpass landslide stability.In this paper,we mainly focus on the conditions of tunnel construction crossing the landslide as the research direction,and the influence of tunnel crossing the landslide body stability is studied by theoretical analysis,numerical calculation,and model test.Firstly,by referring to a large number of literature,the research methods on the stability of the tunnel-landslide system are sorted out,and the current research achievements in this field are summarized.Secondly,the types of tunnel underpass landslide are divided,and mechanical analysis models of the orthogonal system,parallel system,and skew-intersecting system are established respectively by means of conditional assumptions.Then,the numerical analysis of the tunnel underpass landslide model under different parameters is carried out by using the finite element software calculation method.Finally,the spatial-temporal evolution law of mechanical behavior of tunnel underpass landslide was simulated by the design laboratory model test,and the accuracy and reliability of the theoretical analysis and numerical analysis conclusions in this paper were verified.The main research contents are as follows:(1)Based on a lot of investigation and induction,three typical geomechanical models of tunnel underpass landslide are summarized: orthogonal system,parallel system,and oblique system.According to the spatial position relationship between the tunnel and the landslide,the large deflection beam calculation model and the semiinfinite beam calculation model in the orthogonal system,the elastic beam calculation model in the parallel system,and the composite beam calculation model in the skew system are constructed respectively.(2)Study the mechanical behavior of tunnel and the evolution law of slope stability under different conditions,such as tunnel section shape,excavation method,tunnel underpass location,and tunnel-slide zone spacing.The synergistic change law of stress and strain between tunnel and sliding body is revealed,the optimal tunnel underpass mode is obtained,the minimum safety distance of tunnel underpass and the optimal lining application time are determined.(3)The physical model test of tunnel underpass landslide was designed and improved,the same body model of the sliding body and the sliding belt was proposed,the mechanical behavior of the tunnel-landslide system was revealed,the synergistic relationship between the tunnel and sliding body deformation was obtained,and the accuracy of theoretical analysis and numerical calculation conclusions was demonstrated. |
