基于HHT分析隧道围岩结构爆破累积损伤效应

为确保隧道在循环爆破荷载作用下的使用寿命和稳定性能,提出了基于爆破振动信号分析隧道围岩结构爆破累积损伤效应的新方法。依据监测试验获取的振速时程曲线,采用HHT理论将其变换为瞬时能量谱,对比爆破振动信号波形面积方法,针对质点振动能量分析隧道围岩结构物理力学性质的强弱效应,同时应用LS-DYNA数值软件的重启动命令,通过相同节点2次爆破X方向振速时程曲线验证新方法的准确性。研究结果表明:隧道DK497+286、DK497+291、DK497+296里程点3个方向振动能量均呈现下降变化趋势,说明爆破振动累积荷载对隧道监测点处围岩结构产生了破坏作用,并且垂直方向受爆破累积损伤最为严重,因此,需要根据围岩等级和在围岩等级改变处50 m范围内增加支护强度,保证隧道围岩结构安全。

Blasting Damage Accumulative Effect of Tunnel Surrounding Rock Structure on HHT

In order to ensure the usability and stability of tunnel under cyclic blasting load, a new method based on a blasting vibration signal was proposed to analyze the accumulative damage effect of tunnel surrounding rock structure. The vibration velocity curves were obtained from the field monitoring test, which was transformed into an instant energy spectrum by HHT theory. According to the method of blasting vibration signal fluctuant area, the strong and weak influence of the physical and mechanical properties of tunnel surrounding rock structure was analyzed based on particle vibration energy. In addition, the reboot command of numerical simulation software LS-DYNA was applied to obtain the same node blasting vibration velocity curve of X-direction at twice cyclic blasting, which was aimed to verify the accuracy of the new method. The research results indicated that it has a declining trend in three directions on DK497+286, DK497+291, DK497+296 of the tunnel. The tunnel surrounding the rock structure of the monitoring region is damaged by the blasting vibration accumulative load. The degree of blasting vibration accumulative damage is most serious in the vertical direction. According to the grade of the surrounding rock, increase the support strength within the scope of 50 m for the safety of tunnel surrounding rock structure.