| Rib spalling in working face of soft seams seriously affected safety production, water injection is beneficial to prevent rib spalling. The law of water injection to strengthen coal wall stability is a premise that determines reasonable injection technological parameters and guarantees good engineering effect.Firstly, based on the analysis of rib spalling's mechanism and influencing factors, the effect of pore pressure and coal softening caused by injection on stress and strain of coal mass in front of the working face was simulated and analyzed through FLAC3D program. The results showed that the distressed zone, the plastic area and compressible volume of coal mass increased, which is helpful to relieve rib spalling of coal wall. The law of influence of injection pressure and borehole depth on the stress and strain of coal mass in front of the working face was obtained. Secondly, that the effect of water content and water action time on shear strength of soft coal sample was studied by direct shear test, the results showed that reasonable matching water content and coal-water interaction time improved shear strength of soft coal. Finally, the variation characteristics of radial and axial saturation changed with time was simulated and analyzed, which provide the basis for determining injection pressure, borehole depth and injection time.Based on the law of water injection to strengthen stability of soft coal wall, infusion technological parameters of NO.31101 working face in Zhengzhou Coal Group (Dengfeng) Jiaoxue NO.2 Mining Co., Ltd was determined. The rib spalling of soft coal wall was relieved obviously.
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