School of Resources and Safety Engineering,China University of Mining and Technology (Beijing) Coal Industry Engineering Research Center of Top Coal Caving Mining

为了确定近距离煤层群下行开采下位煤层巷道合理布置位置,采用数值模拟、理论分析、底摩擦试验及现场测试的方法,对残留煤柱下底板应力分布规律、区段煤柱稳定性、巷道围岩变形破坏特征等进行分析。研究表明:10号煤层开采对底板造成的破坏深度波及到11号煤层巷道所在水平;应力降低区距离上位煤层开采残留煤柱水平距离7 m,11号煤层区段煤柱受二次采动影响破坏宽度约4 m,巷道布置中合理内错距应保证大于11 m;模拟试验确定巷道采用内错距14、20 m布置时,围岩可保持相同程度的较好稳定性,为提高资源采出率,内错距选取14 m即可保证安全回采工作;最后对1113工作面进行试验段监测,巷道内错距保守选取15 m,实测结果表明,该布置条件下区段煤柱稳定性较好,巷道两帮移近量为30~220 mm,顶底板移近量为20~110 mm,巷道围岩变形较好控制。

In order to set up the rational layout location of the seam gateway under the downward mining in the contiguous seams,a numericalsimulation,theoretical analysis.foor frictional experiment and site test method were applied to the nalysis on the foor stress distribution law of he remained coal ilar,stability of the sectional coal pillar,suounding rock deformation failure features of the gateway and others. The study showed that No.10 seam mining caused the foo failure depth spread to the level of No.11 seam gateway.The stress reduced zone had a horizontal distance of 7 m to the retained coal pilar in the upper seam mining . Infuenced by the secondary mining.the failure width of the sectonal coal pilar in No.11 seam was about 4 m and the rational iner ofiset distance in the gateway layout should be over 11 m.When the inner ofiset distanceof 14 m and 20 m applied to the gateway layout in the sinmulation experiment,the surounding rock could keep a same degree good stability. In order to improve resource mining rate,the inner offset distance of 14 m selected could ensure a safety mining operation.Finally a monitoring and measuring on experiment section was conducted in No.113 cal mining face and inner offset distance of gateway was selected as 15 m conservatively.The site measurement results showed that under the layout condition,the stability of sectional coal pillar was good,the convergence between two sidewalls along the gateway was 30 ~ 220 mm,the convergence between the roof and foor was 20~110 mm and the surrounding rock deformation of the gateway could be well controlled.

国家重点基础研究发展计划(973计划)资助项目(2013CB227903)；国家自然科学基金面上基金资助项目(51574244)；国家自然科学基金煤炭联合基金资助项目(U1361209)；