盾构切削穿越既有桥梁桩基安全性分析研究

Safety Analysis of Shield Cutting through Existing Bridge Pile Foundations

针对盾构隧道切削穿越既有桥梁桩基的可行性和安全性问题,以某地铁项目的区间盾构隧道施工为依托,首先采用理论计算法,分析盾构切削桩基前后,桩基承载力变化和管片的受力影响,得出安全系数表;再结合MidasGTSNX有限元软件模拟分析盾构切削桩基全过程,选取节点分析桥面位移变化和附近土层位移变化。结果表明:盾构切削桩基前后的桥梁结构安全系数变化较小,结构安全;盾构穿越的过程中,桥面和附近土层均发生沉降,沉降量满足规范要求。

Regarding the feasibility and safety issues of cutting through existing bridge pile foundations in shield tunnels,based on the construction of a certain subway project's interval shield tunnel,theoretical calculation methods are first used to analyze the changes in pile bearing capacity and the influence of pipe segments before and after cutting pile foundations,and a safety factor table is obtained;Then combined with Midas GTS NX finite element software to simulate and analyze the whole process of shield cutting pile foundation,select nodal analysis to analyze the displacement changes of bridge deck and adjacent soil layers.The results show that the safety coefficient of the bridge structure before and after cutting the pile foundation by shield tunneling has a small change,indicating structural safety;During the process of shield tunneling,both the bridge deck and nearby soil layers experienced settlement,and the settlement amount met the require‐ments of the specifications.