坚硬顶板关键岩层弱化技术研究与工程实践

Research and engineering practice on weakening technology of key strata in hard roof

  • 摘要: 【目的】针对下沟煤矿ZF4405工作面硬厚顶板导致的矿压显现剧烈、冲击地压频发等工程难题,提出定向长钻孔水力压裂与顶板爆破切顶卸压协同控制技术,并开展现场工程应用。【方法】通过理论分析、数值模拟与工程验证相结合的研究方法,系统开展了关键层弱化机理研究、工艺参数优化及工程效果评价。【结果】研究结果表明,中粒砂岩关键层厚度与弹性模量是影响顶板稳定性的主控因素,通过建立关键层破断力学模型,确定了压裂钻孔应布置在关键层下位岩体拉应力集中区;采用分阶段复合弱化技术,压裂阶段形成辐射状裂隙网络,爆破阶段实现沿裂隙面的定向扩展,两者协同,使关键层进一步弱化;工程实施后,周期来压步距由22 m缩短至17 m,支架工作阻力峰值降低36%,巷道底鼓量减少76%,顶煤回收率提升8.2%,累计创造经济效益9294万元。监测数据显示,微震事件总能量下降25%,验证了技术体系的有效性。【结论】研究成果为矿井坚硬顶板灾害防治提供了新的技术路径,具有显著的安全经济效益。

     

    Abstract: In response to the technical challenges of severe strata behavior and frequent rock bursts caused by the hard and thick roof in the ZF4405 working face of Xiagou Coal Mine, this paper proposes and implements a collaborative control technology combining directional long-hole hydraulic fracturing with roof blasting pressure relief. Through theoretical analysis, numerical simulation, and engineering verification, systematic research was conducted on the weakening mechanism of key strata, optimization of process parameters, and evaluation of engineering effectiveness. The results show that, The thickness and elastic modulus of the medium-grained sandstone key stratum are the main controlling factors affecting roof stability. By establishing a mechanical model for key stratum fracture, it was determined that fracturing boreholes should be arranged in the tensile stress concentration zone of the rock mass beneath the key stratum; A phased composite weakening technology was adopted, forming a radial fracture network during the fracturing stage and achieving directional expansion along fracture surfaces during the blasting stage, with the synergy of both further weakening the key stratum; After project implementation, the periodic weighting interval was reduced from 22 m to 17 m, the peak working resistance of supports decreased by 36%, roadway floor heave was reduced by 76%, top coal recovery rate increased by 8.2%, and cumulative economic benefits reached 92.94 million yuan. Monitoring data showed a 25% reduction in total microseismic event energy, verifying the effectiveness of the technical system. The research results provide a new technical approach for preventing hard roof disasters in mine.

     

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