临空面对爆破震动强度影响的数值研究

现有岩体爆破破碎理论中,临空面都发挥着极为重要的作用,利用临空面的破岩作用来达到降震的目的成为研究的重点。然现有研究多是理论探讨和现场试验,数值模拟方面鲜有涉及。本文采用LS-DANY有限元程序,定量分析了不同临空面数量时隧道结构的爆破震动响应,从数值上探讨了临空面对隧道爆破震动响应的影响机理;并结合西康二线小瓢沟隧道爆破开挖施工时既有大瓢沟隧道的振速实测数据,验证了数值模拟的合理性。研究结果表明,隧道爆破开挖施工中临空面的合理构造可有效降低既有结构的震动响应,所得结论亦可为新建隧道钻爆施工方案的优选提供理论依据。

Numerical Investigation into Effect of Free Surface on the Response of Blasting Induced Vibration

Free surface plays a crucial role in the theory of rock fragmentation by blasting. The effect of free surface on lowering the vibration of blasting has attracted more and more attention. However, most of published research results are mainly those of theoretical study and field blasting experiment, and there is little on numerical simulation. In this paper, using dynamic software LS-DYNA, the effect of free surface on blast-induced vibration response of existing tunnel structure is numerically studied. And the mechanism of the effect is also numerically investigated. Combining the measured vibration velocity data of the existing Dapiaogou tunnel during xiaopiaogou tunnel construction, the applicability of the presented numerical simulation is verified. The results of the study show that the reasonable creation of free surface could effectively reduce the blast-induced vibration response of the existing structure, and the conclusions in this paper also could provide theoretical foundation for the optimization of blasting scheme in new tunnel.