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以济南轨道交通R1线隧道下穿腊山河段为工程背景,采用理论计算与数值分析相结合的方法,分析盾构穿越不同介质的围岩稳定性特征、盾构推力影响效应及界面参数敏感性。研究结果表明:盾构穿越介质交界时,围岩拱顶沉降表现为先增大后减小,管片主应力呈现先增大后减小又回弹的规律,界面效应影响范围主要为界面前4 m至后10 m;当安全系数为2时,维持岩石介质、土体介质、河道段开挖面稳定的支护应力比分别为0.24~2.80,0.34~1.65,0.54~1.40;岩–土界面效应随介质刚度比和界面倾角的增大而增强,当k≥4和θ≥20°时,界面围岩的推力扰动敏感性更加显著。研究成果对深入研究突变地质界面下开挖面稳定性和灾害预防控制具有重要指导意义。
Taking the engineering of the R1 rail tunnel passing through the Lower Reaches of Leshan section of Jinan Rail Transit, the theoretical calculation and numerical analysis are combined to analyze the stability characteristics of the surrounding rock penetrating shields across different media, the influence of shield thrust and the sensitivity of interface parameters . The results show that when the shield passes through the medium boundary, the settlement of the surrounding rock dome first increases and then decreases, and the principal stress of the segment first increases, then decreases and then rebounds. The influence of the interface effect is mainly on the front 4 m to 10 m. When the safety factor is 2, the support stress ratios for maintaining rock excavation medium, soil medium and river channel excavation face are 0.24-2.80,0.34-1.65 and 0.54-1.40 respectively. Rock-soil The interface effect increases with the stiffness ratio of the medium and the increase of the interface inclination. When k≥4 and θ≥20 °, the thrust perturbation of the surrounding rock is more sensitive. The research results have important guiding significance for further study on the stability of excavation face and disaster prevention and control under catastrophic geological interface.