同舟煤业排土场裂缝研究

Study on Cracks of Waste Dump in Tongzhou Coal Co.,Ltd.

同舟露天煤矿排土场各排土平盘在坡顶线位置及距坡顶线及10m范围内产生多条裂缝,宽度范围10mm^100mm,深度范围200mm^1500mm,边坡稳定性存在安全隐患,易形成滑坡事故。通过裂隙成因分析得出:混合排弃物下沉过程不均匀产生张裂隙;受大气降水,自身比重急剧增加,自重应力加大,本身岩体内部粘聚力由于含水量增加而减少,同时混合岩体内摩擦角减小,表层1m范围内混合黄土直接蠕变开裂;冬季混合排弃物随气温下降而下降,热胀冷缩作用下混合排弃物体积收缩,在排土场平盘任意位置均会产生张裂隙。采用Bishop-Morgenstern-Price模型分析边坡稳定性,现有边坡稳定性满足安全生产要求,不存在发生大面积滑移风险,但需要加强排土场边坡日常管理。

In the waste dumping site of Tongzhou Open-pit Coal Mine,many cracks develop within 10 meters of bench edge,with a width ranging from 10 mm to 100 mm and a depth ranging from 200 mm to 1 500 mm.It is easy to develop a landslide which could be a security threat for slope stability.On the cause analysis of the cracks,the fissures are unevenly generated during the sinking of the mixed waste.Atmospheric precipitation increases specific gravity and geostatic stress of the rock mass.Meanwhile,the internal cohesive force of the rock mass decreases due to the increase of water content,the friction angle of the mixed rock body decreases,and the mixed loess directly creeps and cracks within 1 meter of the surface layer.In winter,the mixed wastes decreases with the temperature drop,and the volume of the mixed wastes shrinks under the thermal expansion and contraction.Cracks generate at any position on the flat plate of the dump.Slope stability analysis,using Bishop-Morgenstern-Price model,concluded that existing slope stability meets safety production requirements,there is no risk of large-scale slip,but it is necessary to strengthen the daily management of the dump slopes.