缓倾煤层采空区滑坡形成机制数值模拟研究

以贵州都匀马达岭滑坡为例,采用离散元方法,研究了缓倾煤层采空区滑坡的变形发展过程,提出了该类矿区滑坡防治建议。研究结果表明:采空区顶板塌陷导致上覆岩层弯曲-沉陷,地表产生沉降变形,同时采空区边界部位产生倾倒式拉裂,在地表形成深大拉裂;采空区上部岩体沉陷变形导致坡脚部位岩层往坡外剪切滑移;中部滑面沿变形后倾向坡外的层面和陡倾节理组合形成阶梯状滑面。滑坡形成机制可概括为由采空区顶板变形引发的阶梯状蠕滑—拉裂—剪切滑移式滑坡。缓倾煤层采空区滑坡的防治应从防止采空区顶板塌陷入手,通过回填矸石或加强顶板的永久支护来防治采空区上覆坡体的变形。

Failure mechanism numerical simulation of mining landslide with gentle bedding coal strata

Taking Madaling landslide in Duyun，Guizhou Province as a case，the deformation- destroy process of landslide with gently inclined coal goaves was studied by the discrete element method.And the prevention and controlling recommendations of this kind of landslides were proposed according to the results.The simulation results indicate that，the collapse of goaf roof leads to overlying strata bending- subsidence，which induced subsidence of the slope surface，and the toppling of the rock mass induces deep surface cracks above the borders of goaves，and the collapse and subsidence of the overlying rock strata causes shearing deformation at the toe of the slope，and the stepped slip surface in the middle part of the slope formes by combination of bedding planes dipping outward and steep joints.As a result，the failure mechanism of mining landslide with gentle bedding strata can be summarized as stepped creeping- crack- shear sliding caused by goaf roof deformation.Therefore，in order to control mining landslide with gentle bedding strata，preventing goaf roof from collapsing should be taken into consideration.Backfilling waste rocks or supporting of the roof should be carried out to prevent the deformation of slope body above the goaf.