Study On The Vibration Characteristic Of Debris Flow Platoon Guide Structure In Operating Conditions

Debris flow is one of the most common geological disaster in mountain area.Debris flow platoon guide structure is a frequently-used means of prevention and controlling for small and medium scale debris flow.This article takes the platoon guide structure in debris flow gully of a section in Sichuan-Tibet highway as the research object,based on the ANSYS Workbench platform,by using ANSYS CFX and ANSYS Transient Structural software analyzed the flow field in the guide structure,and transferred to structure analysis,obtained the vibration characteristic of debris flow platoon guide structure.Based on those characteristic,some optimization suggestion were put forward.The main conclusion show as follow:(1)This article sets 5 different flow conditions range from 12.5m~3/s to 62.5m~3/s.By numerical simulation in flow field in the guide structure under 5 different working conditions,obtained the changing rules of hydrodynamic load in value and distribution,found that the maximum value of hydrodynamic load appears in the bottom of the aqueduct,with the flow of debris flow increases,the value goes up too,the distribution stays steady.In working condition 5,the value reaches the highest to 0.364 MPa.And the velocity increases as the flow gets bigger,the growth trend is relatively steady,in working condition 5,the velocity reaches the highest.(2)By numerical simulation in transient structural analysis under 5 different working conditions,obtained the changing rules of vibration characteristic.As the flow of debris flow increases,the total deformation gets bigger,it appears in the middle of aqueduct bottom and carling,its biggest is 11.8mm in condition 5.As the flow of debris flow increases,the maximum principal stress gets bigger,it appears in the middle of aqueduct bottom.As the flow of debris flow increases,the bending moment gets bigger,it appears in the cross of carling and upstand,which is the weakness of structure.(3)By time-frequency analysis,obtained the main vibration direction is vertical direction.In condition 4,the dominant frequency of vibration velocity and acceleration is about 7Hz.(4)Based on the numerical simulation results,the dangerous and weak section of the structure were found,some optimization suggestion were put forward.It is recommended to set steel rail layer to resist abrasion.In big deformation area,it it better to increase stiffness to resist deformation.