鄂尔多斯黄土沟壑区开采沉陷变形破坏研究

Study on surface deformation and destruction caused by mining subsidence in loess gully area of Ordos

大规模的采矿活动对土地资源、水资源、大气和生物产生的负面影响不容小觑,尤其是井工开采造成大面积地面损毁,具有更长的时间影响尺度和更大的环境治理难度。“煤城”鄂尔多斯地处我国西北生态脆弱区,准格尔煤田为我国西部特大型综合性能源基地,开展典型煤矿开采沉陷变形破坏程度的研究对于矿山环境保护、负效应系统性的修复治理以及正效应资源化的开发利用至关重要。为探究黄土沟壑区由于采煤沉陷导致的地表移动、变形及破坏,选取酸刺沟6^(上)121与黄玉川11401工作面为研究对象,利用概率积分法与数值模拟技术相结合,分析评价了区域开采沉陷特征。研究表明:准格尔煤田受地形起伏、地表高程、煤层厚度大、多煤层重复开采扰动等因素的综合影响,采空区地表各方向的应力与位移呈非连续和非均匀对称分布,高应力位于厚黄土覆盖区;地形起伏区具有变形破坏大和影响范围小的特征,近中心线端产生挤压裂缝,而在远中心线坡度大的陡坎边缘产生张拉裂缝,多平行于工作面推进方向;准格尔煤田内的煤矿多位于黄土沟壑区,台阶状地裂缝显著发育,地表破坏强烈,该区具有较弱的自然修复能力。从时域响应分布来看,走向方向和倾向方向在启动、加速和减缓的时间上的占比分别为0~12.0%、12%~26.8%、26.8%~42.6%和0~10.5%、10.5%~34.6%、34.6%~57.6%。

The negative impact of large-scale mining activities on land resources,water resources,atmosphere and organisms cannot be underestimated.In particular,underground mining caused large-scale ground damage,with a longer time scale and greater environmental governance difficulties.Ordos,the“coal city”,is located in the ecologically fragile area of northwest China.Jungar Coalfield is a superlarge comprehensive energy base in western China.It is very important to study the deformation and damage degree of typical coal mining subsidence for mine environmental protection,systematic repair and treatment of negative effects,and development and utilization of positive effects as resources.In order to explore the surface movement,deformation and destruction caused by mining subsidence in loess gully area,Suancigou 6 upper 121 and Huangyuchuan 11401 working face were selected as research objects.The characteristics of mining subsidence were analyzed and evaluated by using probability integral method and numerical simulation technology.The results showed that:Due to the comprehensive influence of topographic relief,surface elevation,large coal seam thickness,repeated mining disturbance of multiple coal seams and other factors,the stress and displacement in all directions on the surface of Jungar Coalfield was discontinuous,non-uniform and asymmetric.The high stress was located in thick loess covering area.The topographic relief area had the characteristics of large deformation and small influence range.Extrusion cracks are generated near the centerline,while tension cracks are generated at the edge of the steep slope far from the centerline,which are mostly parallel to the advancing direction of the working face.Most of the coal mines in Jungar Coalfield are located in the loess gully area.Stepped ground fissures were significantly developed.The destruction of the surface is strong and the area had weak natural restoration ability.From the time response distribution,the proportion of strike direction and dip direction in the starting,accelerating and slowing down stages is 0~12.0%,12%~26.8%,26.8%~42.6%and 0~10.5%,10.5%~34.6%,34.6%~57.6%respectively.