综放沿空留巷顶板下沉规律与控制

针对综放沿空留巷顶板下沉控制困难问题,揭示了综放沿空留巷顶板下沉规律,建立了顶板下沉力学模型,结合损伤力学和能量守恒理论,推导出了顶板下沉量的理论公式,在此基础上对其影响因素进行了分析,提出了综放沿空留巷顶板下沉控制对策,并进行了工程应用。结果表明:顶板下沉量理论计算公式与现场实测值基本一致;各因素对顶板下沉影响程度依次为:巷旁支护体宽度、直接顶有效弹性模量、基本顶给定载荷、关键块破断位置、巷旁支护体有效弹性模量、巷内支护阻力、巷道宽度、顶煤有效弹性模量。顶板下沉控制对策应围绕关键性影响因素进行,据此提出"锚网索+高强度墩柱+木垛"耦合支护方式,即采用锚杆+锚索+高强度钢筋网进行巷内耦合支护,巷旁采用高强度墩柱支护,并用木垛进行巷旁加强支护。工程应用表明,综放沿空留巷围岩变形稳定,顶板下沉得到了有效控制。

Roof subsidence laws and control technology for gob-side entry retaining in fully-mechanized top-coal caving face

In order to overcome the difficult problems associated with the roof subsidence control of gob-side entry retaining in fully-mechanized top-coal caving face (GERFTCF)，the authors have investigated and found the roof subsidence laws for GERFTCF.A damage mechanics model for GERFTCF roof subsidence was established based on energy conservation and damage mechanics theories，and a calculation formula of roof subsidence was deduced.The factors of roof subsidence were analyzed.Therefore，the authors proposed some control countermeasures for GEFTCF roof subsidence and applied them in a case study.Results show that the theoretical roof subsidence calculation formula is in consistence with the roof subsidence measured in the field.The order of most sensitive factors of roof subsidence is as follows:supporting body width，immediate roof effective elastic modulus，basic roof given loading，key block broken location，supporting body effective elastic modulus，inner support resistance，roadway width，and top-coal effective elastic modulus.Roof subsidence control countermeasures should be taken according to the key influence factors.The control countermeasure of “bolt-net-anchor + high strength pier + pigsty” coupling support is put forward based on the research result.In other words，the bolt-net-anchor is used to support inside roadway and the high strength pier is used to support side roadway，and the pigsty is used to strengthen the support on side roadway.The case study demonstrates that the surrounding rock deformation at GERFTCF is stable，and the roof subsidence has been effectively controlled.