软弱夹层对爆炸应力波传播过程的影响研究

针对含软弱夹层岩体爆炸应力波的传播过程,采用数值模拟的方法,探讨了软弱夹层厚度、位置及角度对爆炸应力波传播的影响规律。研究结果表明:爆炸应力波在软弱夹层界面处发生反射,产生的拉伸应力波使应力波能量在迎波面汇聚,加剧该部分岩体的破坏程度。随着软弱夹层厚度的增加,前方岩体拉应力峰值增长作用由近迎波面岩体向炮孔周边岩体传播,拉应力峰值增长率逐渐提高;同时,夹层阻隔作用增强,后方岩体有效应力峰值衰减加快。软弱夹层与起爆中心的间距减小使得夹层前方岩体拉应力峰值显著增长,而对夹层后方岩体的阻隔作用逐渐减弱。应力波能量主要汇聚在软弱夹层的垂直方向,致使岩体爆破产生的裂缝偏离水平测线方向而向软弱夹层法线方向发展。研究成果可用于指导类似地层隧道爆破施工设计。

A study on the influence of weak interlayer on the propagation process of explosion stress wave

Aiming at the propagation process of explosive stress wave in rock mass with weak interlayer, the influence of thickness, position and angle of weak interlayer on the propagation of explosive stress wave was discussed by numerical simulation.The results show that: the explosive stress wave reflects at the interface of the weak interlayer, and the tensile stress wave makes the energy of the stress wave converge at the upstream, which aggravates the damage degree of this part of rock mass.With the increase of the thickness of weak interlayer, the peak value of tensile stress in front rock mass propagates from near-wave surface to surrounding rock mass, and the peak value of tensile stress increases gradually.Meanwhile, the barrier effect of interlayer increases, and the attenuation of effective stress peak value in back rock mass accelerates.The decrease of the distance between the weak interlayer and the initiation center makes the peak tensile stress of the rock mass in front of the interlayer increase significantly, while the barrier effect on the rock mass behind the interlayer decreases gradually.The energy of stress wave mainly converges in the vertical direction of weak interlayer, which causes the cracks produced by rock blasting to deviate from the horizontal survey line and develop toward the normal direction of weak interlayer.The results can be used to guide the blasting construction design of tunnels in similar strata.