Treatment Of Waterproofing And Excavation Method Subject To Tunnel In Rich-Water And Fault Fracture Zone

Rich-water and Fault fracture problem is inescapable during the construction of mountain tunnel. With the increase of the awareness of environmental protection, ensuring ecosystem balance has become a goal during tunnel construction in rich-water and fault fracture area. This paper mainly studies on the distribution rule of water pressure upon lining with different waterproofing types in subject to rich-water tunnel and the excavation method in fault fracture area. Research is carried out based on the case project of KuiBaLu tunnel in Shenzhen.Scopes and Methodologies:1. Relative literature was collected and made a summary. Based on analysis of the geological report of Kuibalu tunnel, the permeability of surrounding rock was obtained. Research on the distribution rule of tunnel seepage field was carried on with three-dimensional finite-difference simulation and so did the study on the rule of water pressure distribution and coefficient of action on surrounding rock, grouted ring and lining as well.2. Study on the distribution rule of water pressure with different waterproofing and drainage types was carried on. Base on it, the relationship among controlled water discharge, water pressure behind the lining, permeability coefficient of surrounding rock and lining were obtained.3. Study on comparing and selection of surrounding formation influence under three different excavation methods including the benching tunneling construction method, the core soil excavation method and the CD method is carried out with three-dimensional finite-difference simulation.Results:1. The distribution rule of water pressure upon lining in subject to enriched water tunnel is obtained, the value of water pressure was determined. The relationship between water pressure action coefficient and coefficient of permeability and thickness of surrounding rock, grouted ring and lining, controlled drainage volume was also obtained.2. Value of water pressure was determined and relationship between water pressure action coefficient and the permeability coefficient of surrounding rock, the permeability coefficient and thickness of grouted ring, the permeability coefficient of lining, controlled drainage volume were also obtained.3. The reasonable tunnel excavation method in fault fracture zone is obtained.