巷道水力压裂切顶应力转移机理及工程实践

    Stress transfer mechanism and engineering practice of hydraulic fracturing roof cutting in roadway

    • 摘要: 针对采空区坚硬顶板难以垮落,造成巷道矿压显现剧烈的问题,以经坊煤矿八采区运输巷为工程背景,通过理论分析、数值模拟、现场实测的方法,运用水力压裂技术研究了巷道应力转移机理。结果表明:3−8072煤巷向煤柱侧预裂切顶的最佳高度为25 m,最佳角度为30°,切顶后采区运输巷附近高应力明显降低,煤柱侧垂直应力由33.79 MPa降为17.7 MPa,降幅为47.6%;水力压裂后,采区运输巷拱脚处被切断,导致拱脚右移,因处于宏观应力壳大结构下而保持长期稳定;通过该技术可以改变坚硬顶板悬顶结构,阻断高应力向巷道传递,从而对巷道进行了有效保护。

       

      Abstract: Aiming at the problem that the hard roof in the goaf is difficult to collapse, which causes severe mine pressure in the roadway, the transport roadway in the eighth mining area of Jingfang Coal Mine is taken as the engineering background, through theoretical analysis, numerical simulation and field measurement, the stress transfer mechanism of the roadway is studied by using hydraulic fracturing technology. The results show that the optimal height of pre-splitting and roof cutting from the 3-8072 coal roadway to the coal pillar side is 25 m, and the optimal angle is 30°. After roof cutting, the high stress near the transport roadway in the mining area is obviously reduced, and the vertical stress on the coal pillar side is reduced from 33.79 MPa to 17.7 MPa, with a decrease of 47.6 %; after hydraulic fracturing, the arch foot of the transport roadway in the mining area is cut off, as a result, the arch foot moves to the right and remains stable for a long time due to the large structure of the macroscopic stress shell. Through this technology, the hanging roof structure of hard roof can be changed, and the transmission of high stress to roadway can be blocked, thus the roadway is effectively protected.

       

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