Study On Seismic Performance Of Railway Shallow Foundation Abutment

Shallow foundation abutment has become a common form of abutment for railroad bridges because of its shallow excavation depth and convenient construction.However,as the connection part between bridge and road,the abutment often slips and slides in front of the abutment due to the earth pressure behind the abutment,leading to the cracking of the abutment front wall and the bridge superstructure,and even leading to the fall of the beam in serious cases.Therefore,in this paper,a shallow foundation abutment with anchor plate is designed with reference to the seismic design requirements of shallow foundation abutment,and the seismic performance of this new abutment is studied and compared with that of the traditional shallow foundation abutment by using the proposed static test and numerical simulation method.The main work of this paper is as follows:(1)The current research status of the seismic characteristics,model test methods and numerical analysis methods of railroad shallow foundation bridge abutments was systematically summarized by reviewing relevant domestic and foreign literature;the current research status of the structural form,scope of application and damage characteristics of anchored plate retaining structures was summarized.(2)The damage characteristics,bearing capacity,skeleton curve,hysteresis characteristics,energy dissipation capacity and damage mechanism of the soil around the foundation of the abutment(back soil and foundation soil)were investigated under repeated horizontal loading to the front of the abutment through proposed static tests.The results show that the addition of the tension-anchored plate device can significantly improve the bearing capacity of the abutment and limit its horizontal displacement under seismic action.(3)Based on the proposed static test,the finite element analysis method was used to study the mechanism of soil-soil interaction of conventional shallow foundation abutment and shallow foundation abutment with tension-anchored plate.The comparison between the numerical calculation results and the results of the model proposed static test showed that the anchored plate with tension-anchored plate shared the soil pressure at the back of the abutment by squeezing the soil in front of the plate under repeated horizontal loading,which was consistent with the crack development of the tested soil.(4)Based on the finite element analysis model,the seismic performance of shallow foundation abutments with tension bars,anchorage plate arrangement,anchorage plate area to abutment back area ratio,fill parameters and length of tension bars were investigated based on the parameters of shallow foundation abutments with anchorage plates in the test.The results show that the diameter of the reinforcement has a significant effect on the seismic performance of shallow foundation abutments with reinforcement-anchored plates.(5)The demand spectrum reduction method considering the flexibility effect,kinematic effect and damping effect of the foundation soil is established for the characteristic of structural damage caused by soil failure in the proposed static test.The seismic performance evaluation indexes of railroad shallow foundation abutments are improved by integrating relevant research results at home and abroad,and engineering example analysis is carried out.The results show that the seismic performance of shallow foundation abutment with tension-anchored plate is better under the action of high intensity earthquake.