The fault-fracture zone is an important tectonic factor for geological hazards such as cave-in and mud bursting.However,the research on grouting theory and technology of fault treatment develops slowly.Based on the treatment project of water-and-mud inrush hazard at F2 fault in yonglian tunnel,the property of rock mass medium in fault-fracture zone is analyzed,and a grouting conceptual model is established.The grouting control equations of three kinds of medium are built up,to analyze the influence of the rock mass property on the grouting process.Through the grouting test,the grouting process in heterogeneous fault-fracture zone is modeled,during which the diffusion process is analyzed,based on the distribution of slurry veins,variations of grouting pressure and the stress of media.The results show that the rock mass in heterogeneous fault-fracture zone can be classified into three kinds of medium,i.e.,incompact,compressible and compact media; while the slurry diffuses in different forms,i.e.,penetration in incompact media,consolidation in compressible media and split in compact media.In compact media,the grouting diffusion distance is positively related to the number of structural planes of rock mass,and negatively related to the compression modulus of rock mass as well as the grouting rate.According to the results of grouting test,the grouting diffusion process in heterogeneous fault-fracture zone can be divided into two stages,advantage filling and split grouting,and the transition point corresponds to the curve break of grouting pressure from creeping up to sharp down.The advantage filling stage,in which the slurry intensively diffuses and the grouting pressure increasing slowly,occurs mainly in compressible and compact media,while the split grouting stage,in which the grouting pressure rises faster,occurs mainly in incompact media.In order to effectively implement the advantage diffusion of slurry in the treatment process of unfavorable geologic bodies filled with incompact or compressible media,a grouting control technique is proposed,and applied to the treatment project of water-and-mud inrush hazard at F2 fault in yonglian tunnel.The technique was proved to have good grouting treatment effects.
