西双版纳隧道爆破开挖动力学特征及损伤效应

为了研究高地应力作用下软岩隧道的围岩稳定性，以实际工程案例为背景，并采用有限元数值模拟软件ANSYS/LSDYNA和实际监测数据结果，分析了隧道爆破近区距掌子面不同距离处，隧道轮廓面的振动速度分布规律，并结合现场声波测试数据，研究了不同爆破次数作用下，围岩深部不同位置的爆破损伤效应。研究结果表明：(1)在隧道爆破近区，隧道内质点的垂直方向振动速度峰值大于隧道径向方向振动速度峰值大于隧道轴向方向振动速度峰值，并且在隧道质点垂直方向，隧道底板和隧道边墙的振动速度较大，而隧道顶部的振动速度次之，隧道拱肩和拱脚处最小；(2)隧道合振动速度峰值出现在隧道未开挖区，同时隧道未开挖区的质点振动速度衰减较慢；(3)随着爆破次数的增加，围岩不同深度处的声波速度呈逐渐衰减的变化趋势，但爆破振动对于围岩损伤范围有限。

Dynamic Mechanical Characteristics and Damage Effects of Tunnel Blasting Excavation in Xishuangbanna

The aim of this study is to investigate the sorrounding rock stability of soft rock tunnel under high geostress. The vibration velocity of rock mass near blasting at different distances from the blast face was analyzed by using numerical simulation software ANSYS/LSDYNA and field monitoring data. Meanwhile, the blasting damage effect on surrounding rock under different number of blastings was studied. Results demonstrated: (1) In the area near blasting, the peak vibration velocity of particles in the tunnel was larger in vertical direction than that in radial direction and axial direction sequently. The vibration velocity in vertical direction in the bottom and sidewall of tunnel were larger than that in tunnel crest, and far more greater than those in arch shoulder and arch foot. (2) The peak joint vibration velocity was found in the unexcavated area of the tunnel, and the vibration velocity of particles in the unexcavated area of the tunnel decayed more slowly. (3) With the increase in the number of blasting, the acoustic velocity at different depths of the surrounding rock showed a trend of gradual decay; but the blasting vibration had a limited damage to the surrounding rock in terms of damage range.