采动影响下水力致裂前后煤层顶板应力变化规律  

Stress variation regularity of the roof strata owing to the coal mining pre-&-pro hydraulic fracture of the coal seam roof

作　　者：高厚 陈卫忠[1,3] 邢天海[4] 郑有雷[4] 钟坤 GAO Hou;CHEN Wei-zhong;XING Tian-hai;ZHENG You-lei;ZHONG Kun(State Key Laboratory of Geomechanics and Geotechnical Engineering,Institute of Rock and Soil Mechanics,Chinese Academy of Sciences,Wuhan 430071,China;University of Chinese Academy of Sciences,Beijing 100049,China;Geotechnical and Structural Engineering Research Center,Shandong University,Jinan 250061,China;Jisan Coal Mine,Yanzhou Coal Mining Company Ltd.,Jining 272000,Shandong,China)

机构地区：[1]中国科学院武汉岩土力学研究所,岩土力学与工程国家重点实验室,武汉430071 [2]中国科学院大学,北京100049 [3]山东大学岩土与结构工程研究中心,济南250061 [4]兖州煤业股份有限公司济三煤矿,山东济宁272000

出　　处：《安全与环境学报》2020年第2期554-559,共6页Journal of Safety and Environment

基　　金：国家重点研发计划项目(2018YFF01014200);国家重点基础研究发展计划(973计划)项目(2015CB057906);国家自然科学基金-雅砻江联合基金项目(U1765108)。

摘　　要：煤层顶板水力致裂是防治冲击地压的重要手段之一。为了研究水力致裂对采动过程中顶板岩层三维应力变化规律的影响,现场开展了煤层顶板水力致裂试验,采用光纤光栅三维应力传感器,监测得到了水力致裂前后工作面推进过程中的顶板岩层三维应力。结果表明:采动影响下,工作面前方顶板岩层中3个方向正应力均不断增加,直至达到应力峰值,其中竖直方向正应力增加幅度明显大于水平方向正应力增加幅度;水力致裂后,应力峰值位置约从工作面前方11 m向深部移动至21 m处,顶板岩层3个方向正应力的增加幅度均有所降低,其中竖直方向正应力增幅的降低程度最大,约从153%降低至94%;水力致裂可以改变采动影响下顶板岩层三维应力的变化规律,尤其是支承压力的变化规律,从而预防冲击地压的发生。The present paper is to identify and determine the influence of the hydraulic fracture on the 3-D stress variation regularity of the roof strata in the process of mining while carrying out the hydraulic fracture of coal seam roof,that is,one of the most important means to prevent from the rockburst.For the said purpose,we have adopted a new type of Fiber Bragg Grating(FBG)sensor.In doing so,we have first of all measured the original rock stress.And then,we have established the stress on-line monitoring system.And,finally,we have been keeping on doing the monitoring practice of the 3-D stress of the roof strata while managing to advance the working face pre-&-pro through the hydraulic fracture.The results of our efforts show that the original rock stress is not conducive to the stability of the working face roadway,and its support should be strengthened.And,due to the mining activities,the normal stresses of the 3 directions in the roof strata tend to increase gradually till reaching the peak value,with the vertical normal stress increasing much more quickly than the horizontal normal ones.And,then,the stresses turn to gradually decrease sharply,which can verify the classical underground pressure theory.And,it can be found that,without the influence of hydraulic fracture,the mining influential scope can be extended to about 110 meters long in front of the working face,with the rapid influential scope being spread to about 45 meters.At the same time,the stress peak position can be pushed about 11 meters long in front of the working face.Thus,in turn,after the hydraulic fracture took place,the mining influential scope can basically stay unchanged.However,the rapid influential scope is likely to increase to about 50 meters long in front of the working face,and the stress peak position may turn to move to about 21 meters in front of the working face.In such a situation,the increasing extent of the normal stress in the 3 directions may decrease at the stress peak position and the decreasing degree of the vertical norma

关 键 词：安全工程 水力致裂 顶板岩层 三维应力监测 变化规律 冲击地压 

分 类 号：X936[环境科学与工程—安全科学]