复杂环境下隧道楔形掏槽合理延期时间优化研究

Study on optimization of reasonable delay time of tunnel wedge cut in complex environment

为探究楔形掏槽不同延期起爆时间对地表振动影响规律,采用基于ANSYS/LS-DYNA的流固耦合算法对楔形掏槽爆破参数进行优化,分析掏槽孔微差爆破对掏槽区域破碎效果的影响与地表振速响应规律。研究结果表明:掏槽区域岩石爆破效果受延期时间影响较大且存在1个阈值,延期时间超过5 ms后自由面方向的掏槽区域内岩石破碎程度未贯通。同时,相较于同时起爆,隧道地表监测点在不同微差时间下降振率变化范围为14%~68%,变化速率呈先快后慢的趋势。而边墙与底板测点降振率受微差时间影响较小。在满足爆破效果的基础上,选择产生最小振动峰值的延期时间5 ms进行现场试验,现场实测峰值与数值模拟得出结果误差在10.32%,说明利用数值模拟的方法研究爆破振动是合理可行的。研究结果可为相关隧道掏槽孔爆破延期时间选择提供依据和参考。

To explore the influence of different delayed detonation time of wedge cut on the ground vibration,the fluid structure coupling algorithm based on ANSYS/LS-DYNA was adopted to optimize the wedge cut blasting parameters,and the influence of the millisecond blasting of cut hole on the crushing effect of cut area and the ground vibration velocity response law were analyzed.The results show that the blasting effect of rock in the cut area is greatly affected by the delay time and there is a threshold value.After the delay time exceeds 5 ms,the degree of rock fragmentation in the cut area in the free surface direction is not connected.At the same time,compared with simultaneous detonation,the vibration reduction rate of tunnel ground monitoring points decreases by 14%~68%in different microsecond time,showing a overall trend of fast first and then slow.However,the vibration reduction rate of side wall and floor measuring points are less affected by the millisecond time.On the basis of satisfying the blasting effect,the delay time of 5 ms that produces the minimum vibration peak value is selected for field test,and the error between the measured peak value and the numerical simulation result is 10.32%,which shows that the numerical simulation method is reasonable and feasible to study the blasting vibration.The research results can provide basis and reference for the selection of delay time of the relevant tunnel cut hole blasting.