顶煤破坏过程及影响因素分析

Top-coal failure process and its influencing factors in longwall top-coal caving mining

根据顶煤边界条件的不同将其破坏过程划分为煤壁前、后方两个阶段;分析煤壁前方顶煤在支承压力影响区内的受载特征,得到其应力路径历史,认为顶煤水平应力变化对其破坏危险性系数影响程度高于垂直应力;建立煤壁后方控顶范围内顶煤稳定性分析模型,得到该区域上下位顶煤分别在顶板回转和支架反复支撑下破坏危险性系数分布特征;分析顶煤危险性系数影响因素,得到开采深度愈大、煤层强度愈低、裂隙发育程度愈高、顶煤厚度愈小、顶板载荷愈大、采动影响程度愈明显,顶煤破坏危险性系数愈大。

According to the different conditions of top coal boundary, the top coal damage process is divided into two stages： the damage in front and at the rear of coal wall. Load characteristics of the top coal in the supporting area are analyzed, and the stress path history is obtained, which indicates that, the influence of lateral stress variation is more significant than vertical stress on the damage risk coefficient. Stability analysis model is established for the top coal in roof - control area at the rear of coal wall, damage coefficient distribution of the top and bottom top coal in the area under the roof rotation and repeated support are obtained. According to the influencing factors analysis, the top coal damage risk coefficient is positively related with mining depth, fracture development of coal seam, roof load and mining influence, and negatively related with coal seam strength and top coal thickness.