大断面隧道爆破振动速度预测

大断面隧道爆破产生的振动对主洞及邻近支洞的动力稳定性有着重要的影响。结合赣深高铁龙南长大隧道爆破工程实践,采用现场监测与ANSYS/LS-DYNA动力有限元分析相结合的研究方法,分析了主洞开挖爆破作用下,隧道主洞及邻近斜井支洞围岩中的爆破振动速度响应特征,并基于最小二乘法原理,分析并建立了主洞及斜井两侧围岩中最大质点振动速度处的爆破振动速度预测模型。研究结果表明:主洞水平轴向与水平切向振动速度拱腰处最大,垂直方向振动速度拱顶最大;主洞与斜井交汇区域振动速度不再随着爆心距的增加而减小,而出现小幅的增大,为主洞爆破施工作用下的危险区域,需重点防护。

Prediction of Blasting Vibration Velocity for Large-section Tunnel Blasting

The blasting vibration of large-section tunnel excavation has a significant influence on the dynamic stability of the main tunnel and the adjacent inclined shaft.According to the blasting engineering case of Longnan tunnel in Jiangxi-Shenzhen high-speed railway,the blasting vibration velocity response characteristics of the main tunnel and its adjacent inclined shaft branches under blasting excavation were analyzed by using the method of on-site monitoring and ANSYS/LS-DYNA dynamic finite element analysis.Based on the principle of least squares method,the prediction model of blasting vibration velocity at both sides of the main tunnel and the inclined shaft was analyzed and established.The results showed that the maximum longitudinal and transverse vibration velocities are at the waist of the arch and the maximum vertical vibration velocity was at the vault.The vibration velocity at the intersection of the main tunnel and the inclined shaft no longer decreased with the increase of the distance from the blast source,but increased slightly.The dangerous area under the blasting construction of the main tunnel was recognized as the intersection part and needed to be protected.