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为研究堆积体隧道围岩和支衬体系受力空间变化规律,采用三维弹塑性有限元法模拟隧道施工过程,得到了洞室周边围岩和支护结构应力随掌子面开挖的变化过程。结果表明,隧道开挖对不同部位围岩扰动大小存在较大差异,扰动后拱部围岩应力强度较小,拱脚和边墙围岩应力强度最大,仰拱围岩应力波动较大但量值总体偏小;管棚在隧道开挖前后受力状态发生明显改变,支护和衬砌过程中有微小波动;拱部系统锚杆对于维持围岩临时稳定发挥了一定作用,但其作为永久支护对围岩长期稳定作用不大,锁脚锚杆在下台阶开挖以及隧道长期稳定方面均发挥了重要作用;初支拱部受拉、边墙和拱脚受压显著,其中拱腰、拱脚分别为拉、压控制性截面;与钢筋混凝土强度相比,二衬受力较小,具有较大的强度储备。
In order to study the variation of stress field of the surrounding rock and lining system of the stacked tunnel, the three-dimensional elasto-plastic finite element method was used to simulate the tunnel construction process and the variation of surrounding rock and supporting structure stress along the tunnel surface was obtained . The results show that there is a big difference in the disturbance of surrounding rock mass in different parts of tunnel after excavation. The stress intensity of the surrounding rock mass is smaller after the disturbance, and the stress intensity of the surrounding rock of the arch foot and side wall is the largest. The overall value is small; the stress state of pipe shed changes obviously before and after tunnel excavation, and there is slight fluctuation during the support and lining; the anchor system of arch system plays a certain role in maintaining the temporary stability of surrounding rock. However, Protect the long-term stability of the surrounding rock has little effect on the anchor bolt in the next step excavation and long-term stability of the tunnel have played an important role; first branch of the arch tension, wall and arch feet significant pressure, including arch waist arch Feet were pulled, pressure-controlled cross-section; compared with the strength of reinforced concrete, the second liner less force, with a greater strength reserves.