软弱夹层对隧道光面爆破效果影响机理研究

以一实际隧道为工程依托,采用ANSYS/LS-DYNA数值模拟方法,针对含软弱夹层围岩隧道光面爆破成型效果问题开展研究。根据软弱夹层与隧道光爆层的相对位置关系,对软弱夹层的空间分布形态特征进行归类和概化处理,提出一种适用于分析软弱夹层影响下光爆层爆破成型效果的概化模型;开展软弱夹层对隧道爆破成型效果影响的多工况数值计算,分别从爆炸应力波的传播及爆生气体的楔入2个方面探讨软弱夹层对隧道爆破成型效果的影响机理,推演得到不同软弱夹层赋存状态下隧道爆破成型轮廓分布图式;结合工程实际施工情况,提出软弱夹层条件下隧道超欠挖爆破控制措施并进行爆破试验验证。结果表明,推演的软弱夹层条件下爆破成型与实际吻合较好;爆破参数调整后,隧道爆破成型效果理想。

Study on the influence mechanism of weak interlayer on tunnel smooth blasting effect

Based on an actual tunnel, ANSYS/LS-DYNA numerical simulation method was adopted to study the tunnel smooth blasting effect of surrounding rock with weak interlayer. According to the relative positional relationship between the weak interlayer and the tunnel smooth blasting layer, the spatial distribution characteristics of the weak interlayer were classified and generalized. A generalization model suitable for analyzing the blasting molding effect of smooth blasting layer under the influence of weak interlayer was proposed. Then the numerical calculation of multi-working conditions was carried out, and the influence mechanism of weak interlayer on the tunnel blasting effect was discussed from two aspects of the propagation of explosive stress wave and the wedge of explosive gas respectively. The contour distribution schema of tunnel blasting forming under different weak interlayer occurrence state was deduced. Combined with the actual construction situation of the project, the control measures of overbreak and underbreak blasting of the tunnel under the condition of weak interlayer are put forward and the blasting test was carried out. The results show that the calculated blasting molding is in good agreement with the actual conditions. After adjusting the blasting parameters, the tunnel blasting molding effect is ideal.