Dynamic Response Analysis Of Rolling Stones In Mountainous Area Based On Pile-soil Interaction And Superstructure Constraints

With the rapid development of traffic construction capacity in China,high-grade highways are gradually approaching the mountainou areas.As a link between the lines,mountainou bridges are often damaged by the rockfall disaster.Rolling rock disasters will directly affect the use of bridge structures in mountainou areas.In severe cases,rockfall impacts can cause the offset of piers,falling beams and even the collapse of the entire bridge.At present,most scholars have studied the boundary conditions of rockfall impacting bridge piers usually adopting the embedding method,ignoring the influence of the pile-soil interaction and the upper structure constraints.This simplified method can not accurately reflect the real dynamic response of the structure when the rockfall hits the pier.Therefore,it is very necessary to develop the rock-impact impact response analysis of mountain bridges based on pile-soil interaction and superstructure constraints.Based on the above research background,the following research works are carried out.(1)the research background of the mountain bridge rolling stone disaster and the domestic and foreign research status of the rolling stone impact bridge are expounded.The problems and shortcomings of the present scholars are pointed out,and the problems to be solved and the content of the research are put forward.(2)The theory of collision dynamics analysis and the principle of numerical analysis are introduced.The knowledge of ANSYS/LS-DYNA software is described.The problems that need attention in numerical simulation are described.(3)the material constitutive model of LS-DYNA used in numerical simulation is expounded,and the reasonable value range of concrete HJC constitutive parameters in numerical simulation is determined with the help of the existing model test results,so that the numerical simulation of the rolling stone impact bridge pier is more truthful and reliable.(4)When considering the influence of pile-soil interaction and the constraints of the upper structure,the difference between the structural dynamic response of the rock-pierced bridge piers and the traditional method of embedding is taken into consideration.A reasonable simulation method for the boundary conditions is determined to accurately simulate the actual situation.(5)A finite element simulation model was established in combination with engineering examples.Parametric analysis was performed from different rolling stone masses,different roll rock speeds,different impact positions,different types of pier structures,and different impact angles to determine the impact of these parameters on the impact results.The results show that it is not safe to use traditional embedded method boundary calculation.Therefore,when we study the impact of the rockfall impact bridge pier,the effect of the pile-soil interaction and the restraint of the superstructure on the substructure cannot be ignored;the rockfall impacts the pier.The damage was dominated by local damage;many conclusions were obtained through parameterized analysis,which has a strong guiding significance for the design,construction,and maintenance of mountainous bridges.