Study on Seepage Characteristics and Grouting Reinforcement Technology of Jinkouhe Fault of Shaping I Hydropower Station Dam Site

The poor mechanical properties and low strength of fault material make it a controlling factor in many geologic hazards. To research the composition characteristics, distribution characteristics, seepage characteristics, and grouting reinforcement effect of the Jinkouhe fault on the left bank of the Shaping I hydropower dam site, the fault material was analyzed by drilling cores, and X-ray diffraction analysis of the whole rock and clay minerals, sieve tests and permeability tests were carried out on the fault crushed powder rock. The seepage characteristics of the left bank slope of the dam site in its natural state and after water storage were studied based on finite difference software, and the mechanism of fault grouting reinforcement and reinforcement effect were also studied. Conclusion: White pulverized rock and yellow pulverized rock do not exist separately in the Jinkouhe fault zone, but occur at intervals with certain zoning characteristics. The total amount of clay in the yellow pulverized rock is about 4.5 times as much as that in the white pulverized rock, the gradation of the fault material is continuous, the mass percentage of clay grains is less than 10% in most of the samples, and 10–20% in a few samples, and the type of structural facies is of rock debris interbedded with mud type; the permeability coefficient K of white pulverized rock is 5.88 × 10−5 cm/s, which is weakly permeable, and the permeability coefficient K of yellow pulverized rock is 1.87 × 10−6 cm/s, which is slightly permeable; the seepage volume of the Jinkouhe fault can be up to 264.91–381.42 m3/d under the normal water storage level; The programmed grouting simulation code can realize the functions and characteristics such as grouting pressure control, grouting flow monitoring, slurry viscosity time-varying, etc. The influence of grouting pressure on the diffusion radius is “step-type”, the larger the grouting pressure, the larger the effective diffusion radius. The influence of the water-cement ratio on the diffusion radius is in stages, the diffusion radius increases with the increase of the water-cement ratio, and the influence on the diffusion radius is smaller when the water-cement ratio reaches a certain value, the permeability coefficient is positively correlated with the effective diffusion radius, and the porosity is negatively correlated with the diffusion radius.