In the process of underground excavation with weak and broken surrounding rock, high-strength arch support is the primary bearing structure to resist rock pressure, especially after shotcrete layer cracks. Field destruction in underground excavation indicates that, with high ground pressure, the primary failure mode of arch is instability failure, which might lead to sudden loss of strength. Therefore, a quantitative analysis of arch instability in tunnel support design is necessary to avoid insufficient support strength so as to ensure the safety of underground engineering. The research method in this paper is based on the application of convergence-confinement method in underground arch support. The modified assumption of support characteristic curve (SCC) is proposed considering the instability failure of arch. The SCC of I-shaped arch and concrete-filled steel tubular (CFST) arch is constructed, respectively, based on mechanical analysis and verified by numerical simulation. A parametric analysis is also carried out to provide reference for arch design. Ground reaction curves (GRCs) of tunnel surrounding rocks with different lithology and ground stress considering arch failure mode are obtained to study the rock–arch interaction mechanism. The research results provide a theoretical reference for the design and application of arch support in related projects.

在地下软弱破碎的基坑开挖过程中，高强度拱支架是抵抗岩石压力的主要承载结构，尤其是在喷射混凝土层破裂后。地下开挖中的现场破坏表明，在高地面压力下，拱的主要破坏模式是失稳破坏，这可能导致强度突然丧失。因此，有必要对隧道支护设计中拱的不稳定性进行定量分析，以避免支护强度不足，以保证地下工程的安全。本文的研究方法是基于收敛约束法在地下拱支架中的应用。考虑拱的失稳破坏，提出了修正的支撑特性曲线假设。基于力学分析并通过数值模拟验证，分别构造了工字型拱和钢管混凝土拱的SCC。还进行了参数分析，为拱设计提供参考。得到了考虑拱拱破坏模式的具有不同岩性和地应力的隧道围岩的地面反应曲线（GRCs），以研究岩拱相互作用机理。研究结果为相关项目拱支护的设计和应用提供了理论参考。得到了考虑拱拱破坏模式的具有不同岩性和地应力的隧道围岩的地面反应曲线（GRCs），以研究岩拱相互作用机理。研究结果为相关项目拱支护的设计和应用提供了理论参考。得到了考虑拱拱破坏模式的具有不同岩性和地应力的隧道围岩的地面反应曲线（GRCs），以研究岩拱相互作用机理。研究结果为相关项目拱支护的设计和应用提供了理论参考。