延安子长矿区极薄煤层分布广泛,因赋存煤炭为稀缺配焦煤,回采价值较高,但该矿区未有过开采极薄煤层的先例,开采过程中面临支架选型不合理的问题,且国内在该方面的研究成果较少,因此,以禾草沟二号煤矿极薄煤层综采工作面为背景,通过数值模拟、理论分析等研究了极薄煤层综采工作面顶板覆岩结构破断特征及其演化过程,建立了采场顶板岩梁断裂前后力学解析模型,获得了极薄煤层综采工作面直接顶周期破断距,确定了合理支架工作阻力。结果表明:极薄煤层工作面开采初期顶板垮落后会较快的对上覆岩层形成支撑,至顶板极限跨距后,直接顶与基本顶周期破断,且基本顶破断位置位于直接顶破断线前方,两者间存在离层空间,共同回转下沉;工作面液压支架主要受直接顶回转载荷作用,其作用载荷为3980.89kN,确定支架选型为ZZ4000/6.5/13D四柱支撑掩护式液压支架;现场应用后,可以有效发挥支架支护性能,满足采场围岩控制要求。研究成果为国内极薄煤层开采工作面支架选型提供了一定的参考。

Extremely thin coal seam is widely distributed in Zichang mining area of Yan’ an. The coal isscarce in China with coking coal, and the recovery value is high; however, the mining area has no precedent of mining extremely-thin coal seam, and the problem of unreasonable support selection is faced inthe mining process, and there are few research results in this aspect in China, so the mining face of extremely-thin coal seam in Hecaogou No. 2 coal mine was taken as the research object, the fracture characteristics and evolution process of roof overburden structure of fully-mechanized mining face in extremely thin coal seam were analyzed by means of numerical simulation and theoretical analysis, andthe mechanical analysis model before and after the fracture of roof rock beam was established. And adirect roof periodic fracture distance of fully mechanized mining face in extremely thin coal seam wasobtained, with the reasonable working resistance of support determined. The results show that the overlying rock could be supported quickly after the roof caving in the early mining stage of the very thincoal seam face; after reaching the limit span of the roof, the direct top and basic top break periodically,and the basic top break position is in front of the direct top break line; there is a separation space between them, and they turn and sink together. The hydraulic support of the working face is mainly affected by the direct top rotating load; its working load is 3 980. 89 kN, and the support selection is determined to be ZZ4000 / 6. 5 / 13D four-column support and cover hydraulic support. By on-site testing, thesupport performance can be effectively utilized to meet the surrounding rock control requirements of thestope. The research results provide a certain reference for the support selection of the mining face of extremely-thin coal seam in China.