Water inrush caused by the wetting-drying cycle is a difficult problem in tunnel excavation. To investigate the effect of the wetting-drying cycle on the stability of the tunnel surrounding rock, physical experiments and numerical simulations regarding the process of tunnel excavation with different wetting-drying cycle numbers were performed in this study. The evolutions of stress, displacement, and pore water pressure were analyzed. With the increase in cycle number, the pore water pressure, vertical stress, and top-bottom approach of the tunnel surrounding rock increase gradually. And the increasing process could be divided into three stages: slightly increasing stage, slowly increasing stage, and sharply increasing stage, respectively. The failure process of the surrounding rock under the wetting-drying cycle gradually occurs from the roof to side wall, while the baseplate changes slightly. The simulation results showed that the maximum principal stress in the surrounding rock mass of the tunnel increases, while the minimum principal stress decreases. Furthermore, the displacement of the rock mass decreases gradually with the increasing distance from the tunnel surface. By comparing the simulation results with the experimental results, well consistency is shown. The results in this study can provide helpful references for the safe excavation and scientific design of a tunnel under the wetting-drying cycle.

中文翻译：

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干湿循环对隧道围岩变形和渗流行为的影响

干湿循环引起的突水是隧道开挖中的一个难题。为了研究干湿循环对隧道围岩稳定性的影响，本研究对不同干湿循环次数的隧道开挖过程进行了物理实验和数值模拟。分析了应力、位移和孔隙水压力的演变。随着循环次数的增加，隧道围岩的孔隙水压力、竖向应力和顶底趋近逐渐增加。其增长过程可分为三个阶段：分别是微增长阶段、缓慢增长阶段和急剧增长阶段。干湿循环下围岩的破坏过程从顶板到边墙逐渐发生，底板变化不大。模拟结果表明，隧道围岩最大主应力增大，最小主应力减小。此外，随着距隧道表面距离的增加，岩体的位移逐渐减小。通过将模拟结果与实验结果进行比较，表明了良好的一致性。研究结果可为干湿循环下隧道的安全开挖和科学设计提供有益的参考。而最小主应力减小。此外，随着距隧道表面距离的增加，岩体的位移逐渐减小。通过将模拟结果与实验结果进行比较，表明了良好的一致性。研究结果可为干湿循环下隧道的安全开挖和科学设计提供有益的参考。而最小主应力减小。此外，随着距隧道表面距离的增加，岩体的位移逐渐减小。通过将模拟结果与实验结果进行比较，表明了良好的一致性。研究结果可为干湿循环下隧道的安全开挖和科学设计提供有益的参考。