| The research and application of grouting technique comes out in our country relatively late, which starts developing in the early 50s, and after 40 years of research and development, a great progress in grouting technology has been made, especially in the development of the cement grouting material what has entered the world advanced level, the application of grouting technology field also gradually expand in mining, construction, railway and water conservancy and other fields。Based on Xi-Zhuo coal mine air return shaft project, this dissertation focuses on grout diffusion of vertical shaft in fractured rock mass. First of all, according to the statistical analysis of field measured data to calculate the distribution function of the various geometric parameters of rock fracture. The geometrical characteristics of fracture network is generated in distribution function to meet the needs of the simulation parameters. After the motion of rock mass for long period, which deforms and being destroyed, leads to a lot of random distribution of fractures. Fracture of mechanics plays a key role in properties and stability of the mechanism of rock mass. The object of two-dimensional network simulation on stochastic structural plane is the space geometric features inside the structure. first of all, the geometry structure should be simplified, according to the wild field measurement of structural plane occurrence, spacing and trace length data, etc, structural plane geometry parameter characteristic value and probability distribution form is obtained using statistics and probability theory, the construction of the combination of structural plane in the two-dimensional space form is obtained using Monte-Carlo simulation method, the formation of structural plane two-dimensional network model. Then under the theory of damage mechanics and fracture mechanics, the flow of solid rock fracture under the action of damage effect and the constitutive equation of damage evolution of crack is described. Because built-in constitutive model by FLAC3D numerical simulation software has limitations in study of rock fracture damage, Visual studio2005 establishment dynamic link libraries is used to build the constitutive model of damage evolution of crack and then export into FLAC3D, lays the foundation for follow-up study. Second, a vertical shaft well wall grouting with smooth crack width are numerically simulated, the reasons of the rock fracture and the expansion of the breakthrough and gradually instability of rock mass are analyzed, different grouting pressure caused by the yield failure area and crack area crack expansion are compared, the numerical analysis shows that when the grouting pressure is in 1～3 Mpa, fracturing effect is not significant to guarantee the slurry injection, and grouting effect is not obvious; When the pressure grouting to 4 Mpa, due to the surrounding rock fracture splitting, slurry can be spread to the depths of the surrounding rock, which can effectively reinforce the surrounding rock; If the pressure grouting to 6 Mpa, displacement of surrounding rock mutations, and has the trend of lose stability. For this kind of grouting, the pressure should be limited in 5～6 Mpa, which has a better grouting effect. Again, combined with specific engineering, working face of vertical shafts numerical simulation is analyzed, diffusion radius of the fixed points in different time and points is calculated, which shows that when the grouting pressure is below 3 Mpa, grouting is hard to proceed; when the grouting pressure is increased to 6Mpa, the surrounding rock will lose stability; When the grouting pressure is controlled within 4～5 Mpa, the reinforcement effect is good. Finally, the numerical simulation results of the proposed design and parameters are combined with field case to verified the efficiency, the result shows that the strength and stability design requirements are satisfied, which also proves the rationality of the numerical simulation. |
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