Study On Creep Characteristics Of Floor Mudstone And Floor Heave Control Technology In Haulage Gate

Based on the haulage gate of 204 working face in Bin Chang mining area,the deformation and failure law of the floor and the treatment measures of the floor heave are studied by means of laboratory test,theoretical analysis,numerical simulation and field test.The main contents of the work are as follows:(1)The physical and mechanical properties,expansibility and composition of the mudstone are analyzed by the laboratory test method.The research shows that the content of montmorillonite in mudstone is too high and the strength will decrease sharply after water,and it produces larger expansion force.The floor rock is divided into medium expansive soft rock,and the type of the bottom drum is determined to be water expansibility.The creep test of three axes of the floor mudstone was carried out,and the creep mechanical properties of the rock sample under different stress levels were obtained(2)The deformation and failure characteristics of the bottom plate of the 204 working face in Xiaozhuang coal mine are analyzed theoretically.It is determined that the form of the floor heave in the 204 working face of the Xiaozhuang coal mine is the composite type of shear slip and water expansion.The failure of shear strength of rock mass in critical shear slip surface is the main cause of floor heave,and the stress form of bottom plate is simplified as the foundation of roof and coal load.A mechanical model of bottom heave is established according to the theory of limit equilibrium.(3)Considering the creep effect,the feasibility of the method is evaluated through numerical calculation,and the construction parameters are optimized.The numerical results show that the floor heave of the haulage gate is 112mm,the deformation of the surrounding rock is small,the plastic zone expansion is effectively suppressed and the effect of the floor heave is remarkable,indicating that the proposed floor heave treatment scheme is feasible.(4)The field test shows that the floor heave is reduced to 92mm after the floor heave control scheme is adopted,and the construction has little influence on the overall stability of the surrounding rock,and can meet the safety production requirements of the 204 working face.