Stability And Multistage Sliding Mode Formation Mechanism Of Bedding Rock Slopewith A Weak Interlayer

Sliding along the weak layer is the main broken type of bedding rock slope.Due to the physical difference between weak layer and its overlying hard rock,soft and hard rock under the long-term gravity effects will deform in different ways, soft rock present itself in plastic deformation while the hard rock in brittle fracture.Due to the long-term different creep of soft and hard rock, tension cracks are not only developed in a certain part of the landslide, but more common in front side and trailing edge of slope, where multiple tension cracks develop from weak layer through to the earth surface.As for above slopes, based on engineering instance of modern landslides and old landslides of Lujumao landslide areas in Shanxi province, slope stability dynamic changing process is analyzed during slide zone strength reduction under the effects of weak layer creep loss and water weakening, and dynamicchanging laws of slope stability with the hydraulic action by heavy rainfall are further analyzed, besides multistage sliding modes of bedding rock slope are analyzed from mechanism, and the main research contents and results are as follows.(1)Based on the limit equilibrium theory, for the bedding rock slope of Lujumao landslide areas in Shanxi province, landslide geometric parameters such as slope angle(α),strata inclination(β), free height of slope toe(h), length of sliding surface(L)and physical mechanics parameters such as unit weight of landslide mass(γ),cohesion(c) and internal friction angle(φ) of sliding zone are taken to establish mechanism analysis model, tree different types of slope stability model are deduced without the account of seismic and hydraulic action,during the reduction process of geotechnical strength parameters in sliding zone:overall stable slope, local stable slope and unstable slope.(2)For the overall stable slope and local stable slope, through the formula deduction, dynamic analysis diagram of slope instability mode under the effects of the rainfall is established. And traction back and goes forward two kinds of multistage sliding mode of slope are analyzed from the mechanism in the process of heavy rainfall.(3)Considering slope surface geometric parameters and slope mechanical strength parameters of bedding rock slope, critical water height of trailing edge connected cracks and critical rainfall intensity are deduced to determine stability.(4)Though numerical simulation, the stability type and failure mode of the slope which under the effects of rainfall or in the strength parameters reduction process in sliding zone were analyzed, besides rationality of relevant formula is checked.(5)With the engineering instance of Lujumao landslide areas in Shanxi province, multistage sliding mode of old landslides and modern landslides are analyzed from mechanism using the theory of this paper.