Study On The Overall Safety Of High Piled Wharf Under The Condition Of Structural Performance Degradation

With the increase of the service years of wharf and the erosion of the adverse environmental effects of wharf,the structural members and the structural performance of wharf have continuous deterioration,the security issues of overall performance of high-piled wharf in service caused by which can’t be ignored.It has certain theoretical significance and application value for the use safety and risk prevention and control of high-piled wharf in service to carry out the study on the overall working safety under the evolution state of structural performance degradation of high-piled wharf.In this paper,the deterioration of structural members and performance degradation of high-piled wharf under the combined action of chloride ion and stress in marine environment are analyzed and studied.Combined with the degradation analysis of stiffness performance of each member of engineering structure of high-piled wharf,the ANSYS finite element three-dimensional simulation model of high-piled wharf under D-P pile-soil interaction is constructed,and the deformation mechanical indexes of each member of high-piled wharf under different stiffness degradation states and different horizontal loads are studied.The principal component analysis and entropy analysis are used to analyze the main member and secondary members that affect the overall working performance of high-piled wharf under horizontal load.Based on the theory of structural reliability,the time variation of the load effect and structural resistance is considered and the performance function of deformation and anti-bending of wharf structure is constructed.The joint programming analysis of MATLAB and APDL is carried out by using Monte Carlo method,and then the overall safety of high-piled wharf under different stiffness degradation states is studied.(1)The calculation methods of the degradation of mechanical properties of reinforced concrete and structural members of high-piled wharf are recommended.From the perspective of environmental erosion and component material properties,the time-varying curve and simplified calculation formula of each mechanical index are obtained,which is convenient to predict the degradation of mechanical properties of structural members of high-piled wharf according to the service time t.(2)Based on the ANSYS finite element three-dimensional model of high-piled wharf,the displacement development law of structural components of high-piled wharf under different stiffness degradation states and different horizontal loads is studied.The formulas of load-displacement curve under different stiffness degradation states and the formulas of time-varying curve of displacement under different horizontal loads of structural components of high-piled wharf are established.(3)By using the principal component analysis and entropy analysis,the influence of each structural member of high-piled wharf on the overall working performance of the structure under horizontal load is studied.It is concluded that the foundation pile has the greatest influence on the overall working performance of high-piled wharf structure under the action of horizontal load,followed by the crossbeam,longitudinal beam and face-plate.The comprehensive weights of foundation pile,crossbeam,longitudinal beam and face-plate are 39.14%,20.68%,20.61% and 19.57% respectively.From the theoretical analysis,it is concluded that the foundation pile is the most important structural member affecting the structural safety of high-piled wharf.(4)The study establishes the time-varying curve and formula of the failure probability of deformation of high-piled wharf structure.And the study shows that the failure mode of high-piled wharf in the degraded state under horizontal load mainly depends on the structural deformation index.The study results of this paper can provide reference for the prevention and control of structural failure risk of high-piled wharf in service.