The Water Softening Technology Research On The Horizontal Section Comprehensive Mechanized Top-coal Cavingin Steep Seam

Steep and extremely thick seam mecha nized caving section process of top coal,encountered hard, the overa ll strength, rely on the coal mining pressure to take action isdifficult, the need for artificia l weakening of hard top-coal. Softening water injection is thekey technology with safety, environmental protection, efficient and economic advantages.Depth study of injection parameters for solving such difficult problems of top-coal caving,improve the recovery rate is important.Through summa rizing the influence factors of water injection softening coal seam, fromthe view of physica l and chemica l, analyze the water of dama ging mecha nism on coal, andstudy the pressure of water on the strength of coal. On the basis of the above theoretica lanalysis, water injection time, pressure, and the la yout method for determining the softeningparameters are analyzed, which provide the theory basis for water softening.This paper studies the water softening parameters about the B3+4 coal seams in the +586level of Xiao Honggou coal mine. The author tests the moisture content, water absorption andporosity of Xiao Honggou coal mine samples in the laboratory, makes use of ultrasonic testsand unia xial compressive tests to analyze the hydraulic characteristics, the mecha nicalproperties changes under the water, and the dama ge under different conditions about the coalmoisture content.Analysis the surrounding rock displacement & stress in Xiao Honggou coal mine byFLAC3D numerica l simulation software, and determining the seepage scope by RFPA3D.Based on the above analysis, the simulate study that designing to parameters which the sitewater flooding softening on the B3+4 of Xiao Honggou coal mine , and giving specific waterinjection program. the rationa lity that Validate design parameters of water injection to soften, the situation that simulate around which the exploitation of water injection and cross off theroof by RFPA2D numerica l simulation softwareThe research shows that the calculation of water injection parameters on the B3+4 coalseams in the +586 level of Xiao Honggou coal mine, which can achieve top-coal fragmentalsma ll ,easy to take, and the purpose to improve recovery, and reference for the left coal watersoftening injection parameters determination.