Study On The Performance And Test Of Broken Coal Cement Grouting Consolidation In Guobei Coal Mine

Based on the actual geological conditions of 8205 wind roadway in Guobei Coal Mine,aiming at the problems of difficult support and maintenance of loose and fractured coal roadway in coal mine,this paper conducts research by means of on-site coal sampling,laboratory test analysis,numerical simulation and engineering test.Based on the physical and mechanical properties test of coal and cement,the consolidation model of cement coal particle grouting is built by numerical simulation,and the consolidation law of cement grouting in crushed coal is analyzed and verified by taking crushed coal particle and cement particle as the breakthrough point.Finally,the high-pressure rotary jet grouting technology was first tested in coal mine engineering through field test of horizontal high-pressure rotary jet grouting in underground roadway.By synthesizing the contents mentioned in this paper,the following main conclusions are drawn:(1)The geological conditions and characteristics of 8205 wind roadway in Guobei Coal Mine are explained in detail,and the coal body is sampled and crushed on site.Through particle size screening,briquette is made according to the appropriate particle size ratio.The average uniaxial compressive strength of coal body is 1.4 MPa measured in the laboratory under 20 MPa briquetting pressure.(2)Laboratory tests on physical composition and hydration and solidification process of ordinary Portland cement were carried out.The uniaxial compressive strength,solidification rate and viscosity of cement consolidators at different ages were tested under different water-cement ratios.It was determined that the water-cement ratio was between 0.8 and 1.0,and the cement consolidation performance was the best.(3)The basic mechanism of grouting consolidation is analyzed.The uniaxial compressive strength of crushed coal and cement grouting consolidation with different mass ratios is measured in the laboratory.Compared with briquette strength,the consolidation strength is obviously improved.(4)Using PFC2 D discrete element particle flow simulation software,the parameters of coal and cement particles are determined,and the consolidation model of cement coal particle grouting is established.With the help of the micro-particle model,the influence law of porosity change on the consolidation model under different particle ratio and infiltration effect is simulated respectively.(5)In the industrial test,the horizontal high-pressure rotary jet grouting test is innovatively attempted,and this technology test is applied to the reinforcement of coal mine roadway,which provides a new exploration and thought for the reinforcement of broken coal and rock mass grouting in coal mine.This paper has 41 figures,8 tables and 99 references.