Theoretical Research On Seismic Design Of Laterally Loaded Piles Based On Behavior

Due to the advantage of good seismic performance,laterally loaded pile is widely applied to slope,foundation pit,underground engineering,port,etc.However,the seismic design theory of laterally loaded piles,which is still in the stage of post disaster summary,numerical simulation and physical model test,is not mature at present.Therefore,it is necessary to study the seismic design theory of laterally loaded piles.In this paper,the pile-soil coupling dynamic equation,elastic-plastic constitutive relation of pile,seismic response characteristics,influence of structural design parameters on seismic performance,the establishment of structural seismic design system and optimization of seismic design are mainly studied.First of all,based on the appropriate assumption of the pile-soil contact relationship,the dynamic equation of the pile-soil coupling is derived by using the working principle of Winkler elastic foundation beam,and the analytical solution is also obtained.Secondly,assuming that laterally loaded pile can meet the requirement of plane stress state,isotropic hardening and Mises yield criterion,the elastic-plastic constitutive relation of laterally loaded pile is deduced.Once again,using software of ANSYS and LS-DYNA,the seismic response characteristics are studied,and according to the time history response characteristics,the whole process of the structure from elastic state to plastic state is analyzed.On that basis,through analyzing the influence of different design parameter on displacement and elastic-plastic performance of laterally loaded pile under ground motion,the seismic design system of lateral loaded pile based on displacement and elastic-plastic behavior established,and fortification target is also determined.Finally,based on the developed seismic design system,the seismic design optimization of lateral loaded piles is carried out.Through above research,the seismic design theorybased on based on the behavior-displacement and equivalent stress of laterally loaded pile is put forward.The application of established seismic design theory in engineering practice can ensure the people’s life and property safety and improve the economical characteristic of structure.In addition,it also provides technical support for the popularization and application oflaterally loaded pile in seismic field.