| The rock anchor bolts phenomenon of shear failure occurred time to time during the process of coal mine bolt support in roadway.It affects seriously the stability of roadway support,especially in the area of strata joint development around the roadway,where the bolt shearing break is the most frequent.In this paper,the author focuses on the coal mine roadway bolt shearing break problem,accesses to relevant information,through field investigation to determine the main causes of anchor bolt shear breaking coal mine.According to the theoretical analysis,the author put forward the reaming anchor in shear joints way to improve the overall stiffness of the anchoring system,which overall resistance shear performance thereby increasing the anchorage system.By the method of numerical simulation,anchorage stress analysis,anchorage is positive wedge-shaped reaming and reaming cylindrical anchorage three anchoring bolt type with shear displacement,shear deformation and anchor stress as the index.In order to determine the best type of shear joint surface,anchoring is wedge reaming anchor.On the basis of positive wedge reaming and anchorage,the shear displacement and shear load of anchor rod are analyzed by changing the location of reaming.Also,the location of reaming is best at 50 mm.It is the positive wedge-shaped reaming in determining the best position.For all,the author changes the overall strength of surrounding rock,founds in soft rock anchor bolt which is more prone to large shear deformation.Anchorage in hard rock bolt can mobilize rock strength to comprehensive resistance from shear joints tangential load.The corresponding bolt shear test device has been designed and manufactured,and the corresponding test method has been determined.Through laboratory tests,the mechanism of the positive wedge-shaped reaming and anchorage at the shear joint surface is further verified,and the effectiveness of improving the shear performance is also verified. |
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