Study On Deformation Mechanism Of Surrounding Rock In Different Directions Under High Horizontal Stress

At present,the measurement and analysis about in-situ stress indicate that the horizontal stress of the upper crust is mostly horizontal or near horizontal,and the value of horizontal stress is generally higher than that of vertical stress.In recent years,with the increase of mining depth and the influence of tectonic action,some high horizontal stress laneways have appeared.In order to study the deformation mechanism of surrounding rock under high horizontal stress with different heading directions,Taking the roadway in Gaojiapu Coal Mine as the engineering background,applying the method combining theoretical analysis,numerical simulation and field test to study the deformation mechanism of surrounding rock,and giving some suggestions on roadway layout and support,the main results are as follows:(1)The in-situ stress measurement of Gaojiapu Coal Mine was carried out by hollow inclusion triaxial stress relieving method.After measurement,the geostress field in Gaojiapu Coal Mine is mainly horizontal stress,and belongs to the type of horizontal stress field.The maximum horizontal principal stress of the Gaojiapu Coal Mine is between 37.29 and 38.67MPa,which is more than 30MPa,belonging to the super highland stress zone.The azimuth of the maximum horizontal principal stress of the measuring point is concentrated between 227-237 degrees.(2)Based on the theory of elastic mechanics,a mechanical model of roadway is established.Using the theory of complex variable function,the analytical solution of stress distribution in the surrounding rock of rectangular roadway is given considering the support condition.According to the actual section parameters and boundary conditions of the mining roadway in Gaojiapu Coal Mine,the stress distribution law of surrounding rock under the condition of different angles between the roadway and the maximum horizontal principal stress is obtained by using the software MATLAB.(3)Taking Gaojiapu Coal Mine gateway as the engineering background,combined with the measured results of in-situ stress,the roadway excavation model is established by using FLAC3D,and the stress distribution,surrounding rock deformation and plastic zone distribution rule under different angles of roadway and maximum horizontal principal stress are simulated.Combined with the theoretical analysis and numerical simulation results,the deformation mechanism of surrounding rock under different coal roadway under the action of high horizontal stress is revealed.(4)The strata control observation was carried out on two roadways with different angles of the maximum horizontal principal stress angle in the Gaojiapu Coal Mine.The deformation characteristics of the surrounding rock were analyzed from the working resistance of the bolt(cable),the deep displacement of surrounding rock and the surface deformation of surrounding rock,and the reliability of the theoretical analysis was verified.(5)According to the deformation characteristics of surrounding rock in different coal roadway under high level stress,some suggestions about roadway layout and surrounding rock support are given.