| In this paper,through analyzing the external physical properties of coal seam water injection improvement status of domestic research on using the strength theory and the theory of liquid bridge,from the perspective of macro and micro analysis,through the mechanism of coal powder consolidation and mechanical properties after reasonable water injection.Based on the experiment and theoretical analysis,the variation law of the mechanical properties of briquette under different water content is summarized.Based on the field test,it is verified that the effect of coal wall hardening is enhanced after the reasonable water injection of soft coal wall.The main contents and conclusions of this paper are as follows:1.combined with field investigation and experiment,the basic parameters of coal briquette were analyzed.It is concluded that the collected samples have the characteristics of low moisture content,low strength and easy to break.According to the theoretical analysis and experiment,the molding pressure and the ratio of the particle diameter of the briquette were determined.2.using RMT-150B rock mechanics test system has been prepared with different water content of coal samples were single,three axial compression test,through the analysis of the test results in the variation of mechanical properties under different water content of coal.The test results show that under uniaxial compression,with the increase of briquette moisture,uniaxial compressive strength and elastic modulus of coal samples first increased and then decreased,and the Poisson’s ratio with the increase of forming water decreased first and then increased.When the moisture content of coal sample was about 7%,the maximum uniaxial compressive strength was 0.821MPa,the maximum modulus of elasticity was 1.332GPa,and the Poisson’s ratio was the lowest,which was 0.267.With the increase of confining pressure,the compressive strength of briquette increases with the increase of confining pressure at three different confining pressures.Based on the strength criterion,the cohesive force and internal friction angle of coal briquette with different water content are obtained.The results show that the cohesive force and internal friction angle increase with the increase of moisture content.3.through the microscopic analysis of the force of the wet coal particles,the influence of the liquid bridge force on the particles in the micro force is the largest.Based on the analysis of the liquid bridge force model,the mechanism of the effect of different moisture content on the consolidation of wet coal particles is analyzed.The factors affecting the liquid bridge force between particles are analyzed.The theory of consolidation of coal is enriched,which provides a theoretical basis for the reasonable water injection and consolidation of pulverized coal.4.In this thesis,the Zhu Xianzhuang Coal Mine Ⅱ 863 fully mechanized top coal caving face are studied shallow hole injection coal wall.Through the determination and investigation of the moisture injection effect of the coal seam,the effective range of water injection is determined,which is transverse 6m,vertical 1～1.2m.The implementation of coal wall shallow hole injection,range of 1.0～3.6m in the bottom of the coal water content of coal was greatly improved,better wetting,creating favorable conditions for the formation of a certain thickness of the adhesive layer,to prevent the coal wall spalling plays a key role through site visits,after the water injection,the coal wall slice is effectively controlled. |
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