南方复杂条件下的薄煤层开采巷道围岩支护问题及对策

Support problems and solutions of roadway surrounding rock for thin coal seams under complex conditions in Southern China

针对复杂地质条件下南方薄煤层开采巷道出现的大变形与控制等问题,开展了一系列现场调查、理论分析和试验等研究。首先,分析了南方煤层地质条件、巷道变形特点和支护中存在的突出问题,同时进行了大量巷道变形的现场调研;然后,研究了薄煤层巷道变形破坏的影响因素和作用机理,主要体现在泥质岩类的物化膨胀与裂隙扩容、半煤岩巷道接触面滑移、水平构造应力挤压、工程扰动偏应力影响和高瓦斯孔隙压力弱化作用等;最后,阐明了复杂条件下薄煤层开采巷道的控制原理,强调应重视发挥巷道深部稳定岩体的承载能力,增强巷道围岩侧向支护作用,实现高阻让压和改善巷道围岩的整体力学强度等。提出了高强度自动让压桁架锚索支护系统和叠加拱"长、短"密集锚索支护技术,并分别进行了软弱半煤岩巷道的返修控制和松散煤岩体巷道支护技术的现场试验研究。监测表明,支护后的巷道围岩变形量都在可控范围之内,满足生产要求。

In view of a series issues such as the control of surrounding rocks in mine roadway and its large deformation in southern thin coal seam mines with complicated geological conditions,it is necessary to make field investigation,theoretical analysis and field test. First,the deformation characteristics of roadway,the geological conditions in southern coal seams and the outstanding problems in the coal mine roadway support were analyzed in this paper. At the same time,a large amount of roadway deformation fields were investigated.Then,the influence factors and mechanism of the roadway deformation in thin coal seam mines were studied,including the materialized expansion of argillaceous rocks,the weak plane slip at coal-rock roadway,horizontal tectonic stress extrusion,the influence of deviator stress under construction disturbed and the weakening of gas pore pressure,etc.Finally,the control principles of thin coal seam mining roadway under complicated conditions were put forward,such as the bearing capacity of roadway deep-surrounding stable rocks should be emphasized,and the lateral supporting of roadway surrounding rock should be enhanced. There-fore,high resistance and yielding support could be achieved for improving the overall mechanical strength of surrounding rock.According to the control principles,the high strength anchor cable support system with automatic yielding capacity and stacked arch with long and short intensive anchor rope support technology was put forward.The field test of soft coal-rock roadway maintenance control and loose coal-rock roadway supporting technology were studied respectively,the result shows that the surrounding rock deformation values after support were manageable,and meet the production requirements.