彬长矿区“对滑型”黄土滑坡及其形成机制
“Opposite-slide” loess landslides and its formation mechanism in Binchang mining area
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摘要: 近年来由于煤炭资源的高强度开采,黄土沟壑区因采煤沉陷引发的沟谷“对滑型”滑坡发育,且滑坡规模大,稳定性差。以李前—白厢滑坡为例,在现场调查的基础上,采用数值模拟分析的方法,探讨了“对滑型”黄土滑坡的形成机制,总结了“对滑型”滑坡的形成条件。研究结果表明:在工作面跨沟回采过程中,上方黄土层指向采空区中心的位移向量与采煤扰动作用下沿坡体倾斜的位移向量产生动态叠加,导致“对滑型”滑坡的发生,且回采后到达一侧的坡体往往早于先到达一侧坡体滑坡;坡向与回采方向相同的一侧,滑坡类型为推移式,坡向与回采方向相反的一侧,滑坡类型为牵引式,且推移式滑坡规模往往大于牵引式滑坡。“对滑型”滑坡的形成需要具备4个主要条件:黄土坡体、沟谷地貌、采矿扰动、降雨催化。Abstract: In recent years,as the high-intensity exploitation of coal resources,the “ opposite-slide” loess landslides caused by coal mining subsidence were developed,the loess landslides usually have large scale and poor stability. Based on the field survey,this paper takes Liqian-Baixiang landslide as a case,discusses the formation mechanism of “opposite slide” landslide by numerical simulation,and summarizes the produce condition of “ opposite slide” land- slide. The result shows that in thick loess area,surface subsidence is caused by uneven migration of coal seam overly- ing bedrock. In the process of cross valley exploitation,the “opposite-slide” loess landslides is caused by the displace- ment vector of the upper loess layer to the center of the mined out area and the dynamic displacement of the downward displacement vector along the slope of the mining disturbance. And the recovery after arrived at one side of the side slope is often earlier than the arrival of first slope landslide. On one side of the slope to the same as the direction of ex- traction,the landslides are push-type landslides,the other side landslides are pull-type landslides. The pull-type land- slides are often greater than push-type landslides. There are four main conditions for the formation of “opposite-slide” loess landslides:loess slope,gully topography,mining disturbance and rainfall catalysis.