基于盾构下穿立交结构围岩破坏过程及安全稳定性研究

结合工程实例,利用有限元分析软件RFPA,充分考虑材料的非均值性,建立模型对盾构穿越桥基两个不利断面隧道开挖围岩破坏过程进行研究,并对桥基加固前后的围岩破坏过程进行对比,计算出各种情况下的安全系数。计算结果表明:隧道最先在桩端出现裂纹,最终沿隧道上方呈槽型贯通。桥基位置在隧道一侧时比在隧道正上方的安全系数大,同时,桥基加固后,隧道安全储备远高于加固前。

Rock Failure Process and Security Stability of Undercrossing Interchange Based on Shield

Based on engineering practice, by using the material anisotropy, this paper establishes a model to the finite element software, RFPA, and fully considering study the rock failure process course of the two unfavorable cross-sections of shield bridge foundation during the process of tunnel excavation. According to the construction, the calculation gives the safety factors in all conditions by comparing the clay destroy before and after bridge foundation reinforcement. The results show that the earliest crack emerged at the button of pipe, and grew across the top of tunnel in the shape of groove. The safety factor where bridge foundation was aside the tunnel was larger than the one where the foundation was right above the tunnel. Meanwhile, the safety stock after the bridge foundation reinforcement was also much larger than the one before it.