多年冻土隧道开挖稳定性分析

采用通用有限元程序，利用温度结构间接偶合方法，通过数值模拟，分析多年冻土隧道开挖过程中可能出现的应力集中区和围岩变形，以选取合理的开挖方案和衬砌结构形式；通过热应力分析，分析多年冻土隧道施工环境温度场与多年冻土围岩稳定的关系，得出施工环境温度的变化对多年冻土围岩的稳定影响并不是在于其引起的强度变化，而是在于其引起的裂隙状态变化，明确了施工温度场对多年冻土围岩稳定的影响主要表现为因融化造成的局部崩塌，该结论可为多年冻土隧道施工提供依据。

Analysis of Stability of Tunneling a Permafrost Region

By general finite element analysis, temperature-structure indirect couple and numerical simulation, an analysis was made on possible stress concentration and wall rock deformation during tunneling a permafrost region in order to select a reasonable excavating plan and lining structure. The relationship between the stability of wall rock and the temperature field of tunnel construction was analyzed to clarify the influence of temperature on tunneling stability by thermodynamic analysis. It was concluded that the influence of the temperature of construction environment on the stability of wall rock did not consist in the variation of its strength, but in the change of its fissure state. It was clarified that the influence of temperature field on wall rock stability mainly presented partial falling of wall rock caused by thawing of permafrost. It provides a basis to the tunnel construction in permafrost region.