井工开采对露天矿边坡稳定性影响的试验研究

Experimental study of impact of underground mining on stability of open pit slope

露天边坡的稳定性是关乎矿山安全生产的重要因素之一。以安家岭露天煤矿29211工作面开采为例,采用相似材料模型试验研究方法,研究井工开采对露天矿边坡变形破裂过程的影响。试验结果表明:29211采面的推进使得上覆岩层发生垮落和下沉变形,形成"拱式"结构,对边坡产生较大的水平推力作用,导致边坡向临空面方向发生较大的水平位移,同时也造成了边坡不同程度的拉裂和沉降变形;当29211工作面推进至合理停采线2时,边坡岩体内出现局部裂缝,推进至设计停采线时,边坡岩体内裂缝已逐渐形成并贯通至坡底,因此,29211工作面推进至合理停采线2时为适宜停采位置;29211工作面开采完毕后工作面中部正上方沉降量最大,边坡岩体最大下沉量约为8 m,边坡体内裂缝逐渐贯通,有被挤出的趋势。研究结果对露天矿现场开采安全提供理论指导。

The open pit slope stability is one of the main problems for the safe production of coal mine project. It has become the main factor of production in coal mine. Taking working face 29211 of Anjialing open pit for example, the impact of underground mining on deformation and rupture process of open pit slope is analyzed by similar material model test. Similar model tests results show that the“arch”structure formed by overburden deformation leads to a great horizontal displacement toward the free surface of slope;and it also results in varying degrees of tensile failure. When working face 29211 advancing to reasonable stopping line 2, local cracks appear in the slope rock mass. The clacks gradually run through and extend to the bottom of the slope when advancing to design stopping line. So, reasonable stopping line 2 is suitable for the location of the stop mining. The above of working face 29211 is the biggest settlement; and the maximum amount of subsidence is about 8 m. The slope which includes through cracks has an extruded trend. The results provide theoretical guidances for safety of open pit exploitation.