密集钻孔弱化坚硬顶板机理的数值模拟及应用研究
Numerical simulation on mechanisms of dense drilling for weakening roofs and its application in roof control
马军强 1李学华 2姚强岭 2夏泽 2徐强 2山长昊 2Andrey SIDORENKO 3Aleksei APARIN3
作者信息
- 1. Key Laboratory of Deep Coal Resource Mining(Ministry of Education),China University of Mining and Technology,Xuzhou 221116,China;Faculty of Mining Engineering,Saint Petersburg Mining University,Saint Petersburg 199106,Russia;School of Mines,China University of Mining and Technology,Xuzhou 221116,China
- 2. Key Laboratory of Deep Coal Resource Mining(Ministry of Education),China University of Mining and Technology,Xuzhou 221116,China;School of Mines,China University of Mining and Technology,Xuzhou 221116,China
- 3. Faculty of Mining Engineering,Saint Petersburg Mining University,Saint Petersburg 199106,Russia
- 折叠
摘要
煤矿坚硬顶板工作面回采后形成的侧向悬臂梁结构导致邻近工作面回采巷道和煤柱处于高应力状态,使得邻近工作面回采巷道围岩矿压显现剧烈.本文提出了一种密集钻孔诱导形成非连续弱面弱化坚硬顶板的技术方法.根据察哈素煤矿31315工作面的工程地质条件,采用颗粒流数值计算软件PFC2D建立了数值计算模型,研究了密集钻孔周围的应力响应机制和裂缝扩展规律.研究发现,密集钻孔开挖后,钻孔周围岩体因受集中应力而出现渐进性破坏并形成以最小水平主应力方向为长轴,最大水平主应力方向为短轴的椭圆形卸压区.同时,当钻孔直径(D)由30 mm增加到133 mm时,卸压区面积比(λ)从0增加到6.42%,卸压区宽度比(μ)从11.55%增加到54.6%.当钻孔间距(L)从300 mm增加到700 mm时,λ从30.86%减小到9.74%,µ从63.9%减小到33.2%,表明采用较大的直径和较小的间距能够提高密集钻孔对坚硬顶板岩层的弱化程度及卸压效果.现场工业性试验结果表明,密集钻孔诱导形成的非连续弱面有效地弱化了顶板岩层的强度,促进了工作面回采后侧向悬臂结构及时垮落,优化了巷道围岩所处的应力环境,保证了工作面生产安全.本研究为煤矿坚硬顶板的控制方案提供了一种新的技术方法.
Abstract
This study proposed a method of dense drilling that could induce the formation of a discontinuous surface to weaken the roof.According to the geological conditions of the Chahasu coal mine,a PFC2D numerical model was established to explore the stress response mechanism and crack expansion law around dense drilling.The study found that,after the dense drilling excavation,progressive damage occurred around the boreholes,and then an elliptical pressure relief zone was created concentric with the direction of the minimum horizontal principal stress as the long-axis and the direction of the maximum horizontal principal stress as the short-axis.Meanwhile,the cumulative area ratio of pixels(λ)increased from 0 to 6.42%and the pressure relief zone width ratio(µ)increased from 11.55%to 54.6%when the drilling diameter increased from 30 mm to 133 mm.When the spacing of drilling was increased from 300 mm and 700 mm,λ decreased from 30.86%to 9.74%;µ decreased from 63.9%to 33.2%,which means that larger diameters and smaller spacing are beneficial for pressure relief.Field tests found that the discontinuous weak surface induced by dense drilling effectively improves the roadway stress environment.This study can provide reference and experience for hard roof control in coal mines.
关键词
密集钻孔/非连续弱面/切顶卸压/回采巷道稳定性/颗粒流数值计算软件(PFC2D)Key words
dense drilling/discontinuous weak surface/pressure relief/roadway stability/PFC2D引用本文复制引用
基金项目
National Natural Science Foundation of China(51874285)
Postgraduate Research&Practice Innovation Program of Jiangsu Province,China(KYCX22_2620)
Graduate Innovation Program of China University of Mining and Technology,China(2022WLKXJ008)
China Scholarship Council(202206420004)
出版年
2023
NETL
NSTL
维普
万方数据