基于PFC-FLAC离散-连续耦合的隧洞开挖与锚杆支护颗粒流模型

Tunnel excavation and bolt support particle flow model based on PFC-FLAC discrete-continuous coupling analysis

针对颗粒离散元程序PFC(particle flow code)无法单独适用于地下洞室开挖与锚杆支护工程尺度的问题,引入PFC-FLAC(fast Lagrangian analysis of continuum)离散-连续耦合分析方法,将求解区域划分为2个子区域:在FLAC程序中建立有限差分单元连续模型用于维持边界地应力值,同时在PFC程序中建立相应尺寸的地下洞室开挖颗粒流模型。经过基于FISH语言二次开发的数据传输设计,2个程序中的连续模型和离散颗粒模型可以进行有效数据交换和连续耦合计算,FLAC耦合边界与PFC墙体保持了良好的变形一致性和应力等价性。经验算,该离散-连续模型的分析结果符合工程经验,可以为从细观角度分析隧洞开挖与支护作用机理提供一定参考。

To solve the problem that usage of the discrete element particle flow code(PFC)program alone cannot fit the scale of underground cavern excavation and bolt support,the PFC-FLAC(fast Lagrangian analysis of continuum)discrete-continuous coupled calculation method is used to divide the solution area into two sub-areas:it establishes finite difference element continuous model in the FLAC program to maintain the boundary stress during excavation process,and particle flow model in PFC program to carry out the underground cavern excavation.On the basis of data transmission design based on FISH language secondary development between ITASCA programs,the continuous model and the discrete particle model in these two programs can perform effective data exchange and continuous coupled calculation,at the same time of which FLAC model coupledboundary maintains good deformation consistency and stress equivalence with PFC walls.The calculation results are in line with engineering experience,which prove that this discrete-continuous model can serve as a reference for analyzing the meso-mechanism of tunnel excavation and bolt support.