近距离下行逐层开采底板应变时空差异特征  

Temporal-spatial variation characteristics of strain in coal seam floor during downward and layer-by-layer mining in ultra-distance coal seams

作　　者：洛锋 曹树刚[2] 李国栋 李勇[2] 李奇贤 LUO Feng;CAO Shugang;LI Guodong;LIYong;LI Qixian(School of Mining and Geomatics,Engineering Technology Research Center of Coal Mine Construction of Hebei Province,Hebei University of Engineering,Handan,Hebei 056038,China;State Key Laboratory of Coal Mine Disaster Dynamics and Control,Chongqing University,Chongqing 400044,China)

机构地区：[1]河北工程大学矿业与测绘工程学院,河北省煤炭矿井建设工程技术研究中心,河北邯郸056038 [2]重庆大学煤矿灾害动力学与控制国家重点实验室,重庆400044

出　　处：《采矿与安全工程学报》2018年第5期997-1004,1013,共9页Journal of Mining & Safety Engineering

基　　金：国家自然科学基金项目(51474039);河北省自然科学基金项目(E2017402166);河北省教育厅科学研究计划项目(QN2015069,BJ2016010)

摘　　要：为了研究近距离煤层群下行逐层开采条件下底板裂隙岩体的应力-应变演化过程,采用相似材料模拟实验方法,结合渝阳煤矿M7、M8煤层的实际地质条件进行模拟分析,获得了一次采动与二次采动条件下煤层群底板应变时空差异特征,并进行了数值模拟验证。研究表明:一次采动条件下,距开切眼较近(减压区范围)与较远的底板岩层分别经历"低应力压缩-卸压膨胀-膨胀稳定"与"高应力压缩-卸压膨胀-重新压实"两个不同应变演化过程。空间上,随工作面推进,底板岩层应变变化量经历由"S"形向"驼峰"状分布曲线过渡的演化过程;二次采动条件下,距开切眼较近位置未出现低应力压缩过程,而是直接出现卸压膨胀然后趋于稳定。空间上,随工作面推进,底板岩层应变变化量经历由拱形分布曲线向"S"形分布曲线过渡的演化过程。两次采动底板各点所经历的应变变化量峰值自开切眼分别呈现"递增"和"∧"形分布。这说明近距离煤层群下行开采过程中,覆岩采空区压实和膨胀区均参与底板应力重新分布过程,应变数值和变化规律与上覆岩层压实范围、原始压力载荷基数、空间边界有关。In order to study the strain evolution process of floor under the downward and layer-by-layer mining in ultra-distance coal seams, based on the geological conditions of M7 and M8 coal seams in Yuyang coal mine, the temporal-spatial variation characteristics of strain in coal seam floor under the primary and the secondary mining are obtained by using the physical simulation and the numerical simulation is used for the purpose of verification. The results show： Under the primary mining, the floor strata which are near（distressed zone） and far from open-off cut experiencing two different strain evolution processes, respectively, which are ＂low stress compression-pressure relief and expansion-stable＂ and ＂high stress compression-pressure relief and expansion-recompress＂. In the space, the strain changing evolution in the floor undergoes a transition from ＂S＂ type to ＂double hump＂ type distribution curve with the longwall mining face advance; Under the secondary mining, the low stress compression process does not appear in the area near the set-up entry instead of the process of ＂pressure relief and expansion and then being stable＂; In the space, the strain changing evolution in the floor undergoes a transition from ＂arch＂ type to ＂S＂ type distribution curve. The peak value of the strain evolution in the floor of those two mining process are different, which shows the ＂increasing＂ and ＂∧＂ type distribution, respectively, from the set-up entry. The distressed zone and stable-pressure zone in gob of overlying coal seams affecting the floor＇s strain evolution process in the downward mining of ultra-distance coal seams. The strain magnitude and changing law has a relationship with the re-compaction rate, the load base of in-suit stress and the space boundary.

关 键 词：近距离煤层 下行开采 底板应变演化 时空差异性 

分 类 号：TD353[矿业工程—矿井建设]