Study On Diffusion Rules And Model Test Of Grouting In Broken Coal

The coal seam in Zhengzhou mining area has the characteristics of broken coal, poor permeability and poor injection. It is difficult to support the broken coal seam roadway. The research object is the broken coal seam in Zhengzhou mining area. Based on the analysis of the diffusion law of broken coal seam grouting, the grouting parameters and grouting technology are studied deeply in the process of grouting with the combination of theoretical analysis, computer simulation and model experiment method. And the broken coal seam grouting technology is designed. The main research results are as follows:1)Through analyzing the physical and chemical properties of broken coal seam and water glass- calcium chlorideslurry, it is show that the porosity of the spherical particles piled up the particles of coal seam is mainly composed of sphere particles arrangement and particle size distribution. When the other parameters are the same, the porosity of the particles with poor separation performance is significantly smaller than the porosity of the fine particles. The nature of the seepage flow in the coal body depends on its rheology. The minimum particle size of the water glass slurry can be injected into the formation is 0.1mm.2)Through the analysis of the broken seam grouting process.it is show that the flow of slurry in the coal body is divided into three stages in the process of grouting: Bubble compaction stage, split flow stage and passive rock mass pressure stage.3)The diffusion velocity of slurry in coal is decreased with the increase of the viscosity of the slurry, and the diffusion rate increases with the increase of the viscosity of the slurry. When the slurry viscosity is less than 0.4Pa.s, the diffusion rate of the slurry in the coal body is relatively small, which is maintained at a relatively high level. When viscosity is more than 0.4Pa.s grout diffusion velocity decreases rapidly and broken coal seam grouting slurry viscosity to less than 0.4Pa.s is appropriate.4)According to the broken coal seam grouting model experimental results, Before grouting the broken coal is loose with great rheology, After grouting, the loose coal is formed into a whole, and a circle of compaction zone is formed around the grouting pipe. After reinforcement, the calcium silicate crystals formed by the reaction between the water glass and calcium chloride can be cemented into a whole. In the coal body, a large number of osmotic pressure reinforcement skeleton is formed, so that the coal body is bonded together, and the strength of the coal body is greatly increased. Pressure test on the coal body, it is known that the hardness of coal body after grouting and reinforcement of granular coal has changed obviously, and the strength of the coal has been increased correspondingly.