Research On Deformation And Failure Mechanism Of Mining Landslide By Physical Simulation Experiments

Mining landslide is due to underground mining influence and overlying rock mass deformation and destruction caused by the landslides.Mined-out area deformation destruction is intricacy process; sliding surface development process in landslide caused by mined-out area deformation is even more complicated, and that has brought great difficulties for slope stability evaluation of mined-out area. Therefore, the research regarding the damage rule of overlying rock mass deformation on mined-out area, has great significance to Mined-out area landslide deformation and failure mechanism analysis and evaluation of slope stability of mined-out area.This paper takes Peak Mine as an example(Peak Mine includs Madaling and Meidongpo, under the effect of lower coal goaf Madaling 190 million m3 landslide happened in 2006 and formed coal hole slope deformation), on the basis of field investigation and geophysical prospecting in mined-out area, using the physical simulation test method, represent the Madaling landslide deformation and failure process, speculated that Meidongpo deformation of slope deformation stages. The results of the mainly includes:(1) Madaling slope and Meddongpo as the flat lining structure slope, slope steep slow, hard on the soft, the upper slope mainly by thick sandstone with a thin layer of carbonaceous shale, terrain is steep, the lower part to the thick layer of thin layered carbonaceous shale, sandstone with coal seam, the terrain is relatively slow. There are 4 layer slope bottom minable seam, form large mined-out area of coal seam mining. Motor ridge coal hole on the east side slope landslide deformation structure characteristics are consistent with the motor ridge, affected by coal bed mining produced in the top five deep cracks, cracks control the slope deformation and failure of Meidongpo.(2) Studies mined-out area distribution characteristics using high density resistivity method, has proven research area distribution in the area of goaf has the A7, A9 two layers, buried depth about between 100-120 m. Most of the mined-out area having been destroyed, local failure in goaf water filling, Madaling landslide boundary and the cracks boundary on Meidongpo below are the mined-out area boundary.(3) Based on field investigation and interpretation of geophysical prospecting results, slow dip goaf landslide geology conceptual model is established, and built a similar ratio of 1:200 physical model, Madaling landslide deformation and failure process, simulation test results show that: First, the rock stress surrounding goaf occur redistribute after coal seam mining, the border area form stress clusters area, the roof form stress unloading area; After coal seam mining settlement of bent at the same time also produces a certain level of mobile, the first is gob roof subsidence, subsidence influence gradually to the surface, at the same time at the top of the rock and slope toe parts produced obvious horizontal displacement. Strata in addition to produce the vertical subsidence and horizontal movement, also produced a large number of cracks, the first is engendered by the boundary area crack, and then formed a large number of cracks in the overburden strata, the formation of crack, then peak with bend subsidence and horizontal movement of overburden rock, crack expanding, after stumping mined-out area boundary and fracture basic, formed the potential sliding surface.(4) The model test to simulate Madaling landslide basic formation potential sliding surface, combined with field investigation, the deformantion and failure process of Madaling landslide includes roof caving, crack extension, plastic flow-tensile splitting, creep, integral sliding five stages. The formation mechanism of Madaling landslide can be summarized as: empty mining subsidence- plastic flow, tensile splitting,- creep shear- landslide. Based on the Madaling landslide deformation and failure mechanism analysis, in combination with Meidongpo fracture and goaf survey, slope deformation are inferred Meidongpo shear creep deformation stage.