受采煤沉陷影响黄土层滑移分析——以甘肃省窑街煤矿为例

Analysis on the landslide in loess layer effected by mining subsidence

滑坡的发生有其特定内因及外因。厚黄土层的滑坡(移)主要由自然条件及人为因素决定。在采煤沉陷区域特别在山区,由于地表的下陷及移动变形更容易发生山坡土体的滑移。文章指出,地下采煤导致上坡方向的黄土层产生具有垂直裂缝的裂隙带。矿区由于人为活动影响,使其周边地表环境发生改变。分析山区地表滑移的力学机制及发生条件,可知黄土层与基岩面间若存在松散土层、千枚岩、泥岩等易于泥化的地质体,在采煤沉陷裂隙带及降水的影响下,一定范围内黄土层就会随湿重的增加而满足失稳条件并沿近乎平面的曲面滑移。文章分析窑街矿区滑坡事例,指出厚黄土层的滑坡灾害除了受地形地貌、地质环境、气候等自然条件控制外,还受人类活动与社会经济条件的影响。即由采煤沉陷及特殊自然地质环境综合造成的厚黄土层滑坡是一种特殊的人为地质灾害。

Underground mining causes land subsidence and deformation. It can induce fragmentary belts with vertical cracks along the edge of subsiding area. There are specified conditions for the occurrence of landslide, and the landslides of thickbeded loess in the Northwest China are controlled by the rock type in the bedrock-loess contact zone and the condition of rainfall. We can get the following knowledge by mechanical analysis on mechanism of land slip and its formation conditions ： if there are weak rocks such as loose soil layer, phyllite, mud-stone, etc. in the disconformable belt between loess and bed rock, the loess layer would lose its stability and start to deform and slip in the condition of subsidence fragmentary belt with vertical cracks and atmospheric water seep into the loess. The slipping mass moves along the curved sliding surface in a certain depth. And the landslide of thick loess layer also causes considerable life and economic losses. The fact of landslide in Yaojie Mining area gives the example for what analyzed above.