The Formation Mechanism, Prevention And Treatment Of The Gob Landslide In Zhupu Town Of Xiaoyi City

Underground mineral mining caused widespread mined-out area, the goaf would destroy the underground rock structure, deformation of rock mass movement damage, surface subsidence, a surface crack and so on, led to the occurrence of landslide, the landslide at the bottom of the building facilities, the village, education facilities and transportation facilities, therefore, the goaf on the cause of the landslide mechanism and the analysis and research of the prevention and control technology has very important significance.This paper, taking Shanxi Province(xiaoyi city column which town goaf landslide as the research object, in carries on the detailed field exploration and underlying mined-out area, on the basis of information collection, first analyzing its development characteristics, at the same time the use of MIDAS-GTS NX numerical simulation software to carry on the numerical simulation, the next down after coal seam mining stress, strain and displacement characteristics of slope change are analyzed, and using strength subtraction, through the analysis of the stability coefficient and the change of plastic deformation distribution, to determine its stability, and sums up the causes of goaf landslide mechanism.Results show that:1.The slope under the effect of initial stress tends to be stable, on underground coal bed mining disturbance role in the mountain, not conducive to the stability of slope body of overlying strata of deterioration, under the weight of overburden stress, deformation of ground surface slope started to slow.With the expansion of the gob area, the mountain stress to readjust, goaf caving roof collapse, overburden sinking under the weight of a bending deformation, deformation transfer to the surface, the surface slowly began to sink.Over time, due to its strength of coal seam is small, there is no necessary protective measures, the original retained in the overlying rock mass coal pillar under the action of gravity stress bending deformation and crush, overburden lose support, cause the goaf roof collapse in large area, because of the goaf edge stress concentration, reflect a certain range in the earth’s surface tension, mined-out area overlying slope under the action of tension, central to the trailing edge of slope body and tensile cracks developing gradually, because of the mined-out area overlying strata subsidence, lead to weak rock slope surface destruction, intensity is reduced, plus, rainfall and groundwater infiltration of slope rock weak plane "soften" role and static water pressure, can lead to the development of slope body tension crack deepened, with weak structure plane in geotechnical engineering are interlinked, shear was carried out on the slope, slope toe shear stress concentration, as a result of the action of water, make slope body gravity stress increases, until the shear stress reaches a critical slope foot, toe is shear failure, sliding surface, slope body formed by water seepage channel, further reduce the strength of the sliding surface, more than when the slide force of landslide sliding resistance to a certain extent, slope began to intense mobile deformation until failure occurs, leading to the occurrence of landslides, eventually new stable slope weight, stress reaches equilibrium.Concrete due to several stages:(1) coal seam mining, the stress imbalance;(2) the subsidence strata subsidence, surface tension,(3) slope trailing edge cracks;(4) the trailing edge cracks, rainfall infiltration;(5) the slope foot shear stress concentration;(6) by shear failure slope foot, sliding surface is completed;(7) landslide.2. Coal seam mining, the goaf, show the vertical downward in the overlying strata subsidence surface under the mountain of slope to the slope displacement, which due to the uneven displacement on the surface of the earth, causing the slope stress imbalance, produce to the uneven displacement of slope toe of slope body, along with the working face advancing, surface subsidence displacement increases gradually, the trailing edge of slope body cracks gradually deepened, slope central cracks expanding, slope rock mass shear damage occurs, the slope foot cut export, sliding surface, landslide occurred in the end.3. With coal seam mining, the goaf roof tensile stress in the central bulge, mined-out area boundary of compressive stress, high, with the working face advancing, tectonite roof caving, boundary coal seam in mined-out area will be fracturing ballooning.4. The coal seam mining induced surface stability, eventually leading to landslides.Through analysis the mined-out area is in a stable state, select the brush party lightening drainage engineering + ZhuangBanQiang + vegetation slope protection of control scheme are goaf comprehensive control of landslide.