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在爆炸载荷作用下,隧道周边会产生大量的径向裂隙,研究在双轴压缩荷载作用下不同位置处径向单裂纹直墙拱形隧道的破坏规律,分两种情况进行研究,一种是裂纹在隧道拱肩或拱顶部位,以拱顶半圆圆心为基点的径向裂纹;另一种是裂纹在隧道底板或边墙部位,其裂纹面与隧道底板、边墙成135°夹角。采用模型试验和数值模拟方法进行研究,模型试验采用水泥砂浆制作隧道模型,数值模拟计算隧道模型裂纹尖端应力强度因子和应力云图,模拟结果与试验结果对比较吻合。结果表明:1裂隙会降低隧道整体的稳定性以及抗压强度;2当裂纹在隧道拱肩或拱顶部位时,裂纹倾角θ=45°时,隧道的稳定性最差,最容易破坏;3当裂纹在隧道底板与边墙交界处时,隧道最容易破坏,整体稳定性最差。
Under the action of explosion load, a large number of radial fractures will be generated around the tunnel. The failure regularity of radial single-crack straight-walled arch tunnels under different biaxial compressive loads is studied. There are two cases: one is Crack in the tunnel shoulder or vault, to the dome center of the circle as the base of the radial crack; the other is the crack in the tunnel floor or wall parts, the crack surface and the tunnel floor, the wall angle of 135 °. The model test and numerical simulation method are used to study. The model test uses cement mortar to make the tunnel model. Numerical simulation is used to calculate the stress intensity factor and stress cloud at the crack tip of the tunnel model. The simulation results are in good agreement with the experimental results. The results show that the fractures will reduce the overall stability and the compressive strength of the tunnel. When the crack is on the shoulder or arch of the tunnel, the stability of the tunnel is worst and the damage is most likely when the crack angle θ = 45 °. 3 When the crack is at the junction of the tunnel floor and the side wall, the tunnel is most likely to be destroyed and the overall stability is the worst.