Research On Grouting Reinforcement Technology Of Large Section Soft Rock Roadway

The return ventilation roadway of Liuliuhongyan Coal Mine in Shanxi Province is a rectangular soft rock roadway with large cross section.Large section soft rock roof span,easy to occur separation,crushing phenomenon,and even roof collapse accident;The thickness of roof soft rock is larger than that of bolt support,which greatly weakens the supporting performance of bolt.Excavation of belt roadway next to the roadway causes further secondary engineering stress disturbance to the return air roadway;The surrounding rock of the roadway contains gangue,and there are a large number of structural planes and cavity areas,which affect the strength of surrounding rock itself.Through theoretical analysis,physical test,numerical simulation and other methods,this paper studies the reinforcement effect of large cross-section soft rock roadway surrounding rock grouting on the strength of broken coal and rock mass,as well as the reinforcement effect of bolt support and applies it to the return wind roadway of Hongyan Coal mine.It provides a certain degree of theoretical basis and technical support for grouting reinforcement.The research contents and results of this paper are as follows::(1)This paper theoretically analyzes the mechanical effects of grouting materials on structural planes,weak roof and weak sides and deduces the formula of peak shear strength of structural planes of good filling grouting materials in three-dimensional state,the formula of increasing the bearing capacity of weak roof under good grouting and the state equation of ultimate stress of the two sides after grouting.(2)The grouting reinforcement effect test of coal and rock mass was carried out to determine the optimal water-binder ratio of the new inorganic grouting material and reveal the grouting recovery effect of coal and rock mass with different degree of crushing;(3)With the backwind roadway of Hongyan Coal mine as the background,the numerical simulation of roof and two sides before and after grouting is carried out,which directly reflects the good control effect of grouting on surrounding rock movement and verifies the application reliability of the formula for improving the bearing capacity of weak roof under the condition of good grouting;(4)The reasons for deformation and failure of the roof and two sides of the surrounding rock of the return ventilation roadway in Hongyan Coal mine were analyzed,and the grouting engineering test was conducted to collect and analyze the actual grouting effect,and the grouting reinforcement effect of soft rock was verified again.