六边形进路开采方式对围岩稳定性影响数值模拟研究

Numerical simulation study on the influence of hexagonal mining approach on surrounding rock stability

基于FLAC3D有限元分析软件,考虑1次充填高度、开采顺序2个因素,分别从位移、应力、塑性区和安全系数对六边形开采围岩稳定性做了定量分析.数值分析结果表明:位移变化最大区域出现于顶板中心,且开采前2步由于岩体经历由原岩向充填体转变阶段,顶板位移会出现突增,随后位移变化速率趋于稳定,位移呈线性增加;应力转移方面,通过应力观测点发现顶板左右两侧应力随开挖进行,会出现先增大后减小的转变,顶板中心位置应力在开挖中期呈现稳定状态,整体充填完成后应力由中心转移到了两侧;塑性区生成区域主要集中于开挖区,其中左右两侧最为严重.结合各方面结果,最终确定理想方案为:1次充填高度为2.6m,开采顺序为隔一采一.

Based on the FLAC3D finite element analysis software,the stability of surrounding rock in hexagonal mining is quantitatively analyzed from displacement,stress result,plastic zone and safety coefficient,taking into account the two factors of the height of primary filling and mining sequence.The results of numerical analysis show that:the area with the largest displacement change occurs in the roof center,and in the first two steps of mining,because the rock mass experiences the transition stage from the original rock to the backfill,the roof displacement will increase abruptly,and then the displacement change rate tends to be stable,and the displacement increases linearly.In terms of stress transfer,it is found from the stress observation point that the stress on the left and right sides of the roof will increase and then decrease with the excavation.The stress at the center of the roof presents a stable state in the middle period of excavation.After the completion of the whole filling,the stress will shift from the center to both sides.The plastic zone is mainly concentrated in the excavation area,and the left and right sides are the most serious.Based on the results of various aspects,the ideal plan is finally determined as follows:the height of primary filling is2.6 m,and the mining sequence is one after every other mining.