基于断层带瓦斯突出的巷道冲击波对围岩的三维动力效应

 为了探索断层带瓦斯突出对巷道围岩的三维动力效应问题，基于峰值超压和速度方程等波动基本理论，结合大平煤矿10.20瓦斯突出事故，应用LS-DYNA与LS-PrePost有限元软件，对冲击波传播特征以及巷道围岩的破坏规律进行了数值模拟。研究结果表明：(1) 沿巷道轴向，在扇形冲击波前锋与巷道顶板交界部位，岩体冲击质点的动力响应最为明显，速度峰值可达到78.015 cm/s，构成巷道围岩最大破坏区；最大破坏区前方为冲击波作用的盲区，岩体动力响应比较弱，本案例盲区长度约为2.1 m；最大破坏区后方为冲击波作用的衰减区。衰减区内围岩仍有侵蚀现象，本案例侵蚀区极限长达280 m；(2) 在巷道横向剖面上，冲击波对巷道侧壁的侵蚀相对较轻。距离掌子面120 m以内的范围内，顶板节点的速度和位移峰值均比侧壁节点的相应值高2～4倍；而120 m以外，顶板和侧壁的速度与位移值逐渐趋于相同。(3) 当岩体较为软弱时，其冲击质点振幅较大。当岩体弹性模量减小到0.05 GPa时，振幅已增加到64.776 mm，巷道破坏效应也相应增大。而硬岩中的冲击波衰减较慢，容易诱发地(矿)震。

THREE-DIMENSIONAL DYNAMIC EFFECT OF GAS BURST SHOCK WAVE ON ROADWAY SURROUNDING ROCK BASED ONFAULT DAMAGE

In order to study the three-dimensional dynamic effect of roadway surrounding rock caused by gas outburst in fault zone，the propagation characteristics and the failure law of surrounding rock were simulated by LS-DYNA and LS-PrePost based on wave theory such as peak overpressure and speed equation，as well as the 10.20 outburst accident of Daping coal mine.The results show. (1) The particle damage is most serious at the junction of shock wave funnel boundary and roadway roof，and the peak speed can be 78.015 cm/s. Along tunnel axial，there is blind area of blast wave in front of maximal value area(2.1 m)，and decay area behind it. The distance of decay area is 280min this case. (2) The erosion of sidewall caused by shock wave is not serious. In the range with 120 m from extraction face，the velocity and peak displacement of nodes on roof are 2–4 times bigger than that of the sidewall within 120 m to the extraction face，while they gradually tend to be the same when the distance is more than 120m. (3) When the lithology is poor，the amplitude of particle under impact effect is much bigger，and when the elastic modulus of rock mass decreases to 0.05 GPa，the amplitude can increase to 64.776 mm. The damage of roadway becomes more serious and easy to induce earthquake.