Research Of Damage Mechanism And Control Of Cable Anchorage Structure Under Vertical Cyclic Loading

As a kind of active supporting method,the cable anchorage structure,especially the prestressed cable anchorage structure,has become an important technology for the support of the surrounding rock,which is buried deeply,has high stress or developed cracks.Based on the actual load characteristics of anchor cable anchorage structure,a plastic damage model of anchorage mortar unit was put forward.The force and it's conduction characteristics of cable anchorage structure under vertical cyclic loading were studied and the validity of the theoretical model was verified.The experimental results showed that the peak value of shear stress,which is larger in the ordinary anchor structure,moved form shallow to deep in the anchorage section with the cyclic load.The failure zone of anchorage zone of prestressed cable also extended from shallow to deep,which resulted in the relaxation of free section and led to the loss of prestress.The displacement law of cable anchorage model was generally analyzed based on the monitoring data of surrounding rock deformation.It is pointed out that the key to control prestress loss was to lock partially prestress in the anchorage section and realize the graded tension anchorage of prestressed cables,a design method was given and a example was cited.The results showed that the peak value of shear stress in the graded tension anchorage was less than 45%,which could avoid the stress concentration and reduce the prestress loss effectively.Finally,the static,dynamic and deformation analysis of the test specimen model was carried out by ANSYS,the validity of the theoretical model as well as the experimental results and the effectiveness of the graded tension anchorage were verified,the detailed information about the stress distribution of the model was obtained,based on which,the displacement variation function with vertical cyclic loading of the cable anchorage mode was given.