不同弹模工况下隧道爆破震动空洞效应的数值模拟研究

Numerical Simulation Study on the Hollow Effect of Tunnel Blasting Vibration under Different Elastic Modulus

为了对不同岩质条件下的隧道爆破震动空洞效应的影响进行探讨,试验基于实测数据建立的特征值及时程分析方法,建立不同弹性模量工况情形下的三维多场耦合模型,对空洞效应的影响及规律进行统计分析,提出相应的减少空洞效应危害的措施及建议。以实测数据为基础建立的数值模型研究结果表明,空洞效应的发生具有一定的区域性,一般在0~80m范围内容易产生空洞效应,且产生的区域跟围岩情况和周围特定环境相关。在不同弹模工况下,各通道震速的变化促成不同岩质下隧道空洞效应放大倍数的不同,且较硬围岩比较软围岩更容易产生空洞效应的放大现象。工程师们不仅应该对未开挖段地表进行监测,而且应该对已开挖段地表加大监测力度,防止因空洞效应的产生出现安全判据条件失误或者超限现象的发生。

In order to investigate the hollow effect of tunnel blasting vibration under different rocky conditions,based on the measured experimental data to establish the numerical method of Eigenvalue analysis and Time history analysis,a three-dimensional multi-field coupling model is established under the different elastic modulus,and the effects and laws of the hollow effect are analyzed in detail,the corresponding measures and suggestions to reduce the harm of hollow effect are put forward.The two kinds of models of elastic modulus have been established on the basis of the measured data,it shows that the hollow effect occurs with a certain regional,it is a certain correlation with the surrounding rock and the specific environment.Generally speaking,when hard surrounding rock is compared with the soft surrounding rock,it is easy to produce the phenomenon of hollow effect.Engineers should not only monitor the unexcavated section of surface vibration but also should increase the monitoring of the surface of the excavated section in order to prevent the occurrence of safety criterion for the occurrence of void effect,or to prevent the occurrence of the phenomenon of exceeding the limit.