急倾斜煤岩体工程结构特征综合调查

Hybrid investigation of structural characteristics of coal-rock mass in mining steeply inclined coal seams

急倾斜煤层赋存环境复杂,揭示急倾斜煤岩体工程结构特征是建立急倾斜煤层动力学畸变动态防控体系的基础。本文采用钻孔电视、地质雷达、光学钻孔摄像、DR扫描等综合手段进行了调查研究。研究表明:乌鲁木齐矿区地质构造活动频繁,采空区顶板宏观结构致密;急倾斜煤岩体为破坏后再稳定结构,存在松散未压实空洞,但未影响顶板的稳定性;急倾斜煤岩体大体划分为破碎区、塑性区及弹性区3个区域;煤体各向差异性显著,存在大量原生裂纹并夹含硫化物。岩体原生裂隙数量少,岩体试样的各向异性小且多掺杂泥岩或泥质砂岩等胶结物质,为导致采空区出现大面积悬顶及整体性垮落的主因。

In-situ geological settings of mining steeply inclined coal seams is so complex that structural characteristics of coal-rock mass is basis for dynamic control of the coal-rock deterioration.A hybrid investigation including borehole television,geological radar,digital borehole camera and DR scanning.relevant results indicate that the geological structure activity is frequent.With the borehole TV and geological radar monitoring,macro-structure of roof in mined-out area is compact and the macro-structure is quadratic stability after failure.There are abundant uncompacted hollows,which seldom affect the stability of coal-rock masses.According to the data from digital borehole camera,the coal-rock masses can be divided into triple zones including broken zone,plastic zone and elastic zone.In mesco-structure aspect being revealed by DR scanning,anisotropy of coal mass is obvious and there are a lot of original cracks and sulfur compound in the coal mass.On the contrary,the number of original cracks is bare and cementing materials like both mudstone and argillaceous sandstone reduce strength of the structure seriously,which is main causes to induce a large-scale hanging in the roof and caving.