宏泰煤矿回采巷道支护方案优化的FLAC^(3D)数值模拟分析

FLAC^(3D) Numerical Simulation of the Supporting Optimization Scheme of Hongtai Coal Mine

宏泰煤矿26B~#煤层回采巷道原采用的支护方案为顶板布置2排φ18 mm螺纹钢锚杆,锚杆长度为1.6 m,间排距为1 m,巷道底板和两帮不支护。经现场调查分析,在矿山压力作用下,巷道顶板上方出现了裂隙和离层现象,并且巷道顶底板移近量明显。为确保巷道稳定,对原支护方案进行了优化,即对巷道顶板较完整的区域采用螺纹钢锚杆进行支护,对顶板较破碎的区域采用锚索支护。为有效确定巷道顶板锚杆、锚索的布置形式及相关支护参数,采用FLAC^(3D)软件构建了数值模型,分别进行了围岩位移场、围岩应力场以及围岩塑性区的数值模拟分析。结合数值模拟结果确定的优化支护方案为:巷道顶板布置3排锚杆,锚杆长度1.8 m,间排距为0.8 m;当巷道顶板较破碎时,顶板布置2排锚杆和1排锚索,锚杆锚索的间排距均为0.8 m,锚索长度视巷道围岩稳定性情况而定。该方案可供类似矿山回采巷道有效支护提供可靠依据。

The original supporting scheme of 26 B^# stoping roadway of Hongtai Coal Mine can be described as two rows of φ18 mm rebar anchors,the length of anchor is 1. 6 m,the anchor intervals and anchor row spacing are both 1 m,the floor and two sides of roadway are not supported. Through field investigation and analysis,under the action of mine pressures,fissures and separation phenomenons are existed in the upper of roadway roof,and the convergence between roof and floor of the roadway is significant. In order to ensure roadway stability,the original supporting scheme is optimized,the supporting optimization scheme is proposed. The new scheme can be described as the rebar anchor is used as the supporting method of the complete area of roadway floor,the crushing area of roadway floor can be processed by using anchor cable. In order to determine the suitable arrangement method of anchor and anchor cable and some relative important supporting parameters,the numerical simulation model is established by using FLAC^（3D） software,and the numerical simulation of surrounding rock displacement field,surrounding rock stress field and surrounding rock plastic zone. Based on the above numerical simulation results,the supporting optimization scheme can be determined as three rows anchors are set in roadway floor,the length of anchor is 1. 8 m,the anchor intervals and anchor row spacing are both 0. 8 m; two anchors and one anchor cable can be used to deal with the crushing area of roadway floor,the anchor intervals and anchor row spacing are both 0. 8 m,the length of anchor cable can be determined based on roadway surrounding rock stability conditions. The supporting optimization scheme of Hongtai Coal Mine proposed in this paper can provide some reliable reference for the roadway supporting of other mines.