上软下硬地层隧道围岩稳定性量化评价标准研究

通过有限元数值计算,对上部为Ⅴ级围岩、下部为Ⅱ级围岩的典型上软下硬地层隧道围岩稳定性量化评价标准进行了分析研究。首先确定以拱顶最大沉降量和能够反映隧道破坏本质、具有严格力学依据的安全系数作为评价隧道围岩稳定性的双重指标;然后通过数值模拟,对上软下硬地层隧道围岩自稳性进行了研究;并根据围岩自稳曲线,进行组别划分,进而建立了典型上软下硬地层隧道围岩稳定性量化评价标准。研究成果对复合地层隧道围岩稳定性分级标准制定起到了细化和补充作用,可为上软下硬复合地层隧道设计和施工提供参考。

Study on Stability Quantitative Evaluation Standard of Surrounding Rockalong Tunnel with Top Soft and Bottom Hard Stratum

With the finite element numerical calculation,an analysis study was conducted on the stability quantitative evaluation standard of the tunnel surrounding rock in a typical top soft and bottom hard stratum.The top section was a V grade surrounding rock and the bottom section was II grade surrounding rock.The paper firstly determined a max subsidence value of the arch roof and a safety coefficient reflected the destructed features of the tunnel and the strict mechanics basis as the double index to evaluate the stability of the tunnel surrounding rock.Then with the numerical simulation,a study was conducted on the surrounding rock stability of the tunnel in the top soft and bottom hard stratum.According to the self stability curve of the surrounding rock,a group division was conducted and thus the quantitative evaluation standard of the surrounding rock stability in the typical top soft and bottom hard stratum was established.The study results would play a fine and supplementary role to the grading standard development of the surrounding rock stability in the complex stratum tunnel and could provide the references to the design and construction of the top soft and bottom hard complex stratum.