深部厚煤层综放沿空掘巷煤柱合理宽度试验研究

 煤柱合理宽度的确定是影响综放沿空掘巷围岩稳定性的重要因素。以深部厚煤层综放沿空掘巷赵楼煤矿11302工作面轨道巷为工程背景，首次提出一种新型侧向支承压力监测方法，通过现场应力监测和数值模拟相结合的研究方法确定区段煤柱合理留设宽度。现场应力监测与数值模拟结果显示，采空区侧向支承压力影响范围为50～56 m，低应力区宽度为12～15 m，考虑沿空巷道应处于应力降低区内，煤柱留设宽度不应大于7～10 m；同时，从有利于锚杆锚固出发，煤柱宽度不应小于4 m。综合考虑煤柱稳定性、次生灾害控制及煤炭资源回收等因素，最终确定煤柱留设宽度为5 m。采用大型地质力学模型试验与现场试验对煤柱宽度合理性进行验证，结果表明，巷道表面位移均呈现沿空帮＞顶板＞实体帮＞底板的变化趋势，掘巷稳定后，现场实测顶底板移近量最大为271 mm，两帮移近量最大为359 mm，巷道围岩控制效果较好；同时，锚杆、锚索受力均在其屈服范围内，并为回采期间预留充足的余量。研究结果可为类似开采条件下的区段煤柱宽度确定提供参考依据。

EXPERIMENTAL STUDY OF REASONABLE COAL PILLAR WIDTH IN FULLY MECHANIZED TOP COAL CAVING FACE OF DEEP THICK COAL SEAM

Determination of reasonable coal pillar width is key for ensuring stability of surrounding rock of fully mechanized caving roadway driving along next goaf. Taking track roadway of 11302 workface in Zhaolou colliery as the engineering background，a new side abutment pressure monitoring method was proposed；and the reasonable coal pillar width was determined by using the method of field stress monitoring and numerical simulation. Field stress monitoring and numerical analysis results show that the influence scope of workface side abutment pressure is 50–56 m，and low stress zone width is 12–15 m，considering pillar stress environment，pillar width should not be larger than 7–10 m. Meanwhile，considering being propitious to bolt anchoring，width of coal pillar should not be less than 4 m. Various elements such as coal pillar stability，secondary disaster control and resources recovery were considered comprehensively. Finally，the reasonable width of segment pillar is determined as 5 m. Reasonable pillar width is verified by using large-scale geomechanical model test and field test. Monitoring results show that variation of surrounding deformation along the empty wall is largest，followed by roof and entity wall，floor is least. After roadway driving along next goaf stability，roof to floor convergence is 271 mm；two walls convergence is 359 mm；the effect of roadway surrounding rock is well. Bolts and anchors forces are in their yield range；and set aside a sufficient margin for the recovery period. The results can provide a reference for segment pillar setting in other mines with similar mining conditions.