针对极弱胶结软岩强度低、胶结差、易风化、遇水泥化、难锚固的特性，在分析其变形破坏机理的基础上，提出了初次支护采用网喷＋拱形支架、二次支护采用单层钢筋砌碹砼的复合支护方案。采用数值模拟研究了分步开挖对硐室稳定性的影响，并验证了该支护方案的可行性。现场监测结果进一步表明，该支护方案能满足极弱胶结地层中硐室支护的要求，对于极弱胶结地层中硐室施工具有一定借鉴意义。%The weakly cemented strata is characterized by its low strength, poor cementation, problem of susceptibility to weathering and getting muddy, difficulty in anchoring. Based on the analysis of its deformation and breakage, a complex supporting scheme was proposed including an initial wire mesh⁃reinforced shotcrete plus arch support withⅠ⁃steel, and a secondary lining structure of single⁃layer of reinforced concrete. The feasibility of this scheme has been verified through the numerical simulation of the influence of excavation step⁃by⁃step on the chamber stability. The on⁃site monitoring results indicated that such supporting scheme can meet the supporting requirements for chambers in the weakly cemented strata, which is of certain significance for the chamber construction in the weakly⁃cemented strata.
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