爆破开采扰动对巷道围岩稳定性影响的模拟研究

以某金矿Ⅶ号矿体-498m水平开采工作面为研究对象,采用有限元数值仿真分析方法研究了该矿爆破开采扰动对巷道围岩稳定性的影响。研究结果表明:受开挖扰动的影响,巷道顶板的最大主应力减小较为明显。在工作面推进过程中,巷道周边岩体向开挖空间内移动,采掘横巷顶部的位移场沿工作面呈现心型分布,且在采掘横巷与水平沿脉巷交汇处出现的最大位移为6.31mm。随着工作面的推进,采掘横巷围岩的垂直位移呈现增大的趋势,当巷道掘进工作面推进3m以内时,其采掘横巷顶板的垂直位移变化较大,最大增大了60.13%;当巷道掘进工作面推进距离超过3m时,顶板的顶部垂直位移变化不明显,而水平沿脉巷道各监测断面的围岩垂直位移趋于稳定;当工作面推进20m后,可认为开挖对水平巷道围岩的垂直位移没有影响。巷道围岩主要表现为剪切破坏,且巷道临空位置顶板和底板主要表现为拉伸破坏和拉剪复合破坏。

SIMULATION RESEARCH ON THE EFFECT OF BLASTING EXCAVATION DISTURBANCE ON STABILITY OF SURROUNDING ROCK OF TUNNEL

The mining face of Ⅶ orebody at-498 m of a gold mine is used as the research object for studying the effect of blasting excavation disturbance on stability of the stability of surrounding rock based on finite element numerical simulation analysis method.The results showed that maximum principal stress in the roof of tunnel decreased significantly caused by blasting excavation.The surrounding rock moved to the excavated-out area with working surface advanced.The displacement field of tunnel roof presented a heart-shaped distribution,and the maximum displacement at the intersection of mine cross and lateral tunnel was 6.31 mm.With the working-face removing,the vertical displacement of tunnel roof increased.The vertical displacement changed significantly and it increased biggest by 60.13%when the working-face moved less than 3m.Its change was not obvious and the vertical displacement of surrounding rock of the lateral tunnel at various monitoring sections tended to be stable when the working-face moved more than3 m.It was considered that blasting excavation had no effect on the vertical displacement of surrounding rock of the lateral tunnel after moving 20 m.The surrounding rock of tunnel showed a shear failure and the roof and floor mainly showed tensile failure and tensile-shear failure.