CAJ | 학술논문

针对塔山煤矿临空顺槽矿压显现剧烈的问题，进行水力压裂弱化煤层上覆坚硬 K3老顶的现场试验，通过水力压裂期间监测钻孔以及巷道两侧锚杆出水情况与水压的变化分析水力压裂的影响范围，通过水力压裂前后周期来压步距、动载系数、顶板下沉量、两帮移近量、煤壁片帮统计、工作阻力与瓦斯涌出情况，深入分析水力压裂弱化坚硬老顶的特点。试验结果表明：(1)切槽裂隙在水力压裂的作用下其扩展范围不超过55 m；(2)裂缝所处的煤岩体环境使得裂缝扩展的压力时间曲线呈现3种轨迹形态；(3)水力压裂前后，周期来压步距分别为18.69，16.76 m，平均周期来压动载系数分别为1.69，1.53；顶板下沉量与两帮移近量都明显缩小，巷道顶板整体完整；煤壁片帮深度平均值由原来的31.18 m变为7.06 m；瓦斯涌出相对稳定，上隅角瓦斯浓度由原来的0.20%降低为0.15%。工作面顶板完整性和强度得到了弱化，随工作面推进顶板能够及时垮落，5106临空顺槽顶板的压力明显减弱，说明水力压裂的效果良好，研究结果对类似条件下的工作面具有积极的指导意义。
침대탑산매광림공순조광압현현극렬적문제，진행수력압렬약화매층상복견경 K3로정적현장시험，통과수력압렬기간감측찬공이급항도량측묘간출수정황여수압적변화분석수력압렬적영향범위，통과수력압렬전후주기래압보거、동재계수、정판하침량、량방이근량、매벽편방통계、공작조력여와사용출정황，심입분석수력압렬약화견경로정적특점。시험결과표명：(1)절조렬극재수력압렬적작용하기확전범위불초과55 m；(2)렬봉소처적매암체배경사득렬봉확전적압력시간곡선정현3충궤적형태；(3)수력압렬전후，주기래압보거분별위18.69，16.76 m，평균주기래압동재계수분별위1.69，1.53；정판하침량여량방이근량도명현축소，항도정판정체완정；매벽편방심도평균치유원래적31.18 m변위7.06 m；와사용출상대은정，상우각와사농도유원래적0.20%강저위0.15%。공작면정판완정성화강도득도료약화，수공작면추진정판능구급시과락，5106림공순조정판적압력명현감약，설명수력압렬적효과량호，연구결과대유사조건하적공작면구유적겁적지도의의。
The hydraulic fracturing field tests to weaken the hard K3 upper roof above coal layer were conducted when severe problems occurred in the open-air and crossheading strata at Tashan Coal Mine. The water pressures in the boreholes and water oozing from bolt locations at two sides of roadways were monitored during the process of hydraulic fracturing to analyze the range of influence of hydraulic fracturing. The characteristics of weakening the hard roof by hydraulic fracturing were analyzed according to the step size of periodic pressure,the dynamic loading factor,the deflections of roof,the displacements of roadways,the statistical analysis of rib wall and gas discharge before and after hydraulic fracturing. It was found that the range of grooving fractures produced by hydraulic fracturing was no more than 55 m. Three types of the pressure-time curve of crack propagation in the coal and rock mass were obtained. The step sizes of periodic pressure are 18.69 and 16.76 m respectively and the average periodic dynamic pressure factors are 1.69 and 1.53 respectively before and after hydraulic fracturing. Both the deflection of roof and the displacement of roadways were greatly reduced and the roof of the roadways remained unbroken. The average depths of coal wall rib spalling were reduced from the original 31.18 m to 7.06 m. Besides,the gas release is relatively stable. The gas density at the upper corner was reduced from the original 0.20%to 0.15%. Meanwhile,the completeness and strength of the roof at the working front were weakened and roof was dropped as working front proceeds.