爆破扰动诱发地下洞室围岩变形突变机制研究

摘要

In order to study the mechanism of abrupt deformation of surrounding rock,a model of embedding block in the wall is established,and the mechanism of slippage caused by blasting is analyzed theoretically.The horizontal displacement of the block in the inner wall caused by blasting excavation is calculated by using numerical software LS-DYNA.And it is found that the ultra-low friction induced by blasting disturbance leads to the residual displacement of the block which is one of the causes of abrupt deformation mutation.The study shows that under the same lateral pres-sure coefficient,the relative displacement of the block induced by near and far area blasting disturbance exhibits a par-abolic increase with the horizontal in-situ stress.The average value of the block displacement induced by the far area blasting disturbance is about 60%.In addition,the dynamic response of two blocks under blasting disturbance is stud-ied,and it is found that the blasting energy is mainly consumed by the block near the free surface.%为了研究地下洞室边墙围岩变形突变的产生机制,建立了边墙围岩嵌入块体的模型,从理论上分析了块体受到爆破扰动时产生滑移的机理,并采用LS-DYNA数值软件,计算了不同地应力下爆破开挖引起的块体的水平位移,认为爆破扰动诱发超低摩擦效应导致块体产生残余位移是引发变形突变的原因之一.研究结果表明:当侧压力系数相同时,随着水平地应力的增加,近区和远区爆破扰动所诱发的块体相对位移均呈现抛物线状增加,远区的爆破扰动诱发的块体位移平均可达到近区的60%左右.此外,研究了嵌入在边墙围岩内的两个块体在爆破扰动下的动力响应,发现爆破产生的能量主要被靠近临空面一侧的块体吸收消耗.