A Simulation Study On The Mechanical Characteristics Of The Surrounding Rock Of A Deep Roadway Under The Combined Action Of Unloading Disturbance

On the background of excavation unloading and blasting disturbance of the deep roadway in Huize lead zinc mine,simulation analysis is carried out for excavation,dynamic and static combination and true triaxial loading and unloading and loading and unloading disturbance by FLAC3 D,ANSYS,Tecplot.The mechanical evolution rule,failure process and failure mechanism of deep rock mass under unloading and disturbing are studied:(1)Under the effect of excavation,concentrated stress will be generated at the shoulder and inclined foot of the roadway,and the stress concentration of the inclined foot is the most obvious.The maximum deformation is at the roadway,the stress and deformation of the roadway will be deflected toward the inner wall of the roadway near the excavation surface,and has hysteresis.The closer the surrounding rock around the inner wall of the roadway is,the higher the displacement velocity will be,the surrounding rock will show relaxation.The farther away from the roadway inner wall is the smaller the displacement speed,the smaller the deformation space of the surrounding(2)Under disturbance.With the increase of the peak value of dynamic stress,the concentrated stress of the road arch spandrel disappeared,the concentrated stress of the inclined foot increased,and the deformation of the dome and the groud became the largest,while the bottom displacement vector deflected under the action of dynamic stress,and the deformation decreased.Stress and deformation will be deflected toward the inner wall of the tunnel near the excavation surface,and it has hysteresis.With the increase of dynamic stress peak,the roadway surrounding rock can be divided into unloading area,stress concentration area and stress attenuation area.(3)Under true triaxial loading and unloading conditions,the maximum principal stress is mainly distributed on both sides of the hole.Under the action of axial loading,Large concentrated stress generated at the corners of the loaded surface,and the local concentrated stress of the two sidewalls of the hole Themaximum shear stress is gradually far away from the wall of the hole,and the largest deformation area of the specimen continuously changes during different loading stages.The plastic failure of the specimen is caused by the macroscopic plastic zone of the upper right corner and the lower right corner and the plastic zone of the hole wall.Damage,and shear stress plays a dominant role in the destruction of the specimen.(4)Under true triaxial loading and unloading and dynamic disturbance conditions,the concentrated stress is mainly distributed on both sides of the hole and the disturbance loading surface.It is different from the axial static load only,under the action of dynamic stress.There are fragmentary independent stress regions and corrugated stress contours in the upper right corner.When the disturbance stress peak value is greater than 20 MPa,the concentrated stress on the left side wall of the hole is greater than that on the right side wall,and the maximum deformation of the system is located on the unloading surface.The study of strain energy found that the damage was caused by the gradual increase of plastic strain energy.