动压影响下深部回采巷道围岩失稳及支护研究

Research of surrounding rock instability and support of deep mining roadway affected by dynamic pressure

以大同煤矿集团有限责任公司某深部厚煤层综放开采煤矿为背景,通过围岩地质力学测试、井下煤柱应力实测及合理煤柱尺寸确定等方法研究动压影响下深部回采巷道围岩失稳特征及支护方案。研究结果表明:顶板煤体平均抗压强度为32.08 MPa,粗砂岩平均抗压强度为89.85 MPa,4号煤层平均抗压强度为17.61 MPa;测量区域最大水平主应力为26.26 MPa,最小水平主应力为13.39 MPa,垂直应力为15.80 MPa,最大水平主应力方向为N34.4°W,原岩应力场在量值上属于高应力区;一次动压影响阶段,超前支承压力对煤柱的影响范围及影响程度远远小于工作面回采后采动应力对煤柱的影响;二次动压影响阶段,孔深8~18m处煤柱处于弹性核区,合理煤柱宽度至少为55m。提出了14103辅运输巷初始支护设计,现场工业性应用表明:在14102工作面回采期间,巷道有效断面积为巷道掘进断面积的97.5%;14103工作面回采期间,巷道顶底板移近量约为300mm,两帮移近量约为260mm,完全满足矿井安全生产要求。

On the background of one deep thick Datong Coal Mine Group Co., Ltd., surrounding mining roadway affected by dynamic pressure were seam coal mine using fully-mechanized caving mining in rock instability regularity and support scheme of deep studied with methods of surrounding rock geomechanics test, coal pillar stress measurement and reasonable coal pillar size determination. The study results show that mean compressive strength of roof coal, gritstone and No. 4 coal seam is 32.08, 89.85 and 17.61 MPa individually. The maximum horizontal principal stress, the minimum horizontal principal stress and vertical stress of the measured area is 26.26, 13.39 and 15.80 MPa individually, direction of the maximum horizontal principal stress is N34.4°W, and in-situ stress filed belongs to high stress area on numerical value. During period of the first dynamic pressure, influence range and degree on coal pillar of advanced support pressure are far less than the ones of mining-induced stress after working face stoping ahead.During period of the second dynamic pressure, coal pillar located in 8-18 m borehole depth is in elastic kernel area, and reasonable coal pillar width is no less than 55 m. The initial support design of 14103 working face auxiliary transport roadway was proposed. The results of industrial field tests show that effective cross section area is 97.5% as large as excavation cross section after 14102 working face stoping ahead. During stoping 14103 working face, convergence between roof and floor in auxiliary transport roadway is about 300 mm, and convergence between two sides is about 260 mm, which can completely realize mine safety production.