引水隧洞变形破坏机理颗粒流数值模拟研究

RESEARCH ON NUMERICAL SIMULATION OF THE DEFORMATION AND FAILURE MECHANISM OF DIVERSION TUNNEL BASED ON PFC

引水隧洞是水电、核电等能源工程的主要工程结构,受内外水压、复杂工程地质条件的影响,其围岩变形破坏机理较难掌握。本文基于颗粒流分析方法,以伺服边界Wall调整应力状态和空隙率,进而形成不同的地应力组合,得到了合理的细观数值计算模型,能实现任意二维复杂离散颗粒模型的构建,且生成颗粒间重叠量小,在颗粒间黏结力破坏后亦不会造成飞溢现象,在此基础上开展参数标定,探讨了不同应力场、结构面分布下的引水隧洞变形破坏机理,可为隧洞开挖破坏机理分析与工程措施确定提供依据。

Diversion tunnel is the primary engineering structure in energy engineering fields, e.g. , hydropower, nuclear power, etc. Due to the effects of the difference between internal and external hydraulic pressure and the complex engineering geological conditions, it is very difficult to understand the deformation failure mechanism of its surrounding rocks. Research in the paper was presented based on the particle flow analysis method, and the different in-situ stress combinations were formed by using servo boundary Wall to adjust the stress state and the porosity. Moreover, a reasonable mesoscopic numeri- cal model was obtained, and this numerical model can achieve the structure of any two-dimensional complex discrete particles and little of the overlap between the particles, and additionally, the overflow phenomenon does not happen after the bonding force was damaged between particles. On this basis, the parameter calibration was conducted, and the deformation failure mechanisms of diversion tunnel under different stress fields and the structure plane distributions were discussed, which can provide a reference for the analysis on failure mechanism and the determination of engineering measures to excavate tunnel.