Research On Nonlinear Vibration Identification Of Anchorage State Of Prestressed Anchor Cable

After more than one hundred years of research and promotion,the anchoring technology has a wider application field and the technology is becoming more and more perfect.However,it is still faced with the constant expansion of the project construction scale,the difficulty continues to increase,and the various adverse factors in the long-term service process.Whether it is the overall support capacity of the prestressed anchor cable or whether each component can play its role,it is affected by the internal anchoring force.Therefore,the detection of the anchoring force of the prestressed anchor cable is an important part of safe production.Based on the structural dynamics and the nonlinear vibration characteristics of the structure,this paper studies the lateral vibration characteristics of the prestressed anchor cable,proposes a signal index extraction method based on AMD for signal processing,and tests the prestressed anchor cable for different contact surface conditions The components were subjected to dynamic testing,and the test process was simulated using ABAQUS.The non-linear vibration characteristics of the prestressed anchor cable under multiple indexes were studied.The main results are as follows:(1)Combined with the condition parameters of the contact surface,a numerical example analysis was conducted using the lateral vibration characteristics of the prestressed anchor cable.The relationship between the size of the anchoring force,the condition of the contact surface and the natural frequency of lateral vibration is proved;the anchoring force mainly affects the system dynamic test results by changing the nonlinear characteristics of the contact interface between the anchor pad and the rock body to be anchored.(2)The signal processing flow of the prestressed anchor cable dynamic testing test based on the AMD principle was established,and the extraction method of the frequency index and the non-linear index in the non-destructive testing test of the prestressed anchor cable anchoring force was determined.(3)The non-destructive testing of prestressed anchor cable was conducted in the laboratory,and the previous theoretical derivation and analysis were tested and verified.Under different tensile conditions,the anchoring force of the specimens with different contact surface conditions was tested with multiple indicators The nonlinear vibration response signal of the interface between the anchor plate and the concrete worktable was successfully measured,and the natural frequency index and nonlinear index were extracted.(4)The relationship between the natural frequency index of the transverse vibration of the prestressed anchor cable,the non-linear vibration characteristic index and its internal tensile force was verified;in order to better simulate the study of the prestressed anchor cable under actual service working conditions,a drop was made in the experiment Segment curve,and explored the effect of different contact surface conditions on nonlinear vibration characteristics.(5)A three-dimensional finite element model of the prestressed anchor cable was established using ABAQUS,and the modal vibration mode of the prestressed anchor cable was calculated using the simplified model.The modal analysis of the cable body vibration added a theoretical basis for the filtering method.The whole test process was simulated to verify the conclusions of the experiment and other variables that may have an impact on the measurement index were calculated.