Study On The Application Of Cement Based Glass Fiber Slurry In Grouting And Water Shutoff Of Karst Tunnel

The water inrush and mud burst encountered in tunnel construction under complicated geological conditions have become one of the major disasters affecting the construction of karst tunnels. Large scale and frequent water inrush disasters not only endanger the safety of engineering construction, but also seriously affect the progress of the project, causing huge losses to the project.Grouting technology is one of the most effective ways to solve the karst tunnel water inrush disaster, material and slurry reinforcement plugging reinforcement effect and improving the conditions of tunnel surrounding rock grouting reinforcement, has been applied widely. The grouting technique is related to the integrated technology of many disciplines, including grouting material in grouting technology plays a key role in the cement based glass fiber slurry material as a kind of cement based composite materials, because of its distinctive characteristics and attention. Based on theoretical analysis, experimental study, numerical simulation and engineering application of combined research methods, and relying on high speed Liwan Qiyueshan tunnel grouting and engineering project reinforcement , researching on the diffusion mechanism analysis of cement-based grouts, experimental study on the mechanical properties of cement based glass fiber materials,the grout materials through the analysis of reinforcement effect numerical simulation, combined with the application in Qiyueshan tunnel, formulate reasonable technical scheme, obtained the following conclusions:(1) The theoretical formula of crack seepage based on the study of seepage law of grout materials in the crack, and established the flow model of grout, grout derived materials required grouting volume formula; established in cement-based composite materials under dynamic diffusion model of water conditions, derived cement-based composite materials under dynamic the diffusion distance formula under the condition of water.(2) The test analyzes the mechanical properties of cement based glass fiber materials, respectively from the compressive strength test,tensile test, bending test and impermeability, analysis of cement slurry in different types and different content of glass fiber with properties of age,get the best dosage test conditions, and get the Cem-FIL60 type glass fiber mixing amount for 0.5% to improve the performance of the mechanical has obvious effect.(3) Numerical model is established by FLAC3D software, analyzed the tunnel after excavation on the surrounding rock broken position of grouting reinforcement, were studied in four different conditions, namely the formation of grouting circle respectively in 0m, 3m, 5m and 7m under the condition of stress field and displacement field change situation.(4) Combination of Qiyueshan tunnel grouting and reinforcement engineering, key hole grouting scheme applied in engineering construction, the water inrush from different locations and different types of different schemes for making glass fiber; cement slurry grouting problems, put forward a system for the preparation of a new type of slurry through; the inspection hole method, discharge monitoring and analysis of deformation monitoring of surrounding rock grouting effect.