Study Of Dynamic Response And Influencing Factors Of Pile Foundation Of Slope Arch Bridge Under Seismic Action

In the mountainous areas of western of China,there are many high and steep slopes,most of which are located between the Indian Ocean plate and the Asia-Europe plate,where the seismic fault zone is very active.In order to meet the needs of mountain highway route selection and ecological protection,the pile foundations of bridges crossing mountainous areas are inevitably built on slopes.At the present,the research on pile foundations on slopes are mainly focused on static research.Bridge pile foundations on slopes have both anti-sliding and load-bearing characteristics and the force under dynamic load is more complicated than that on flat ground.It has important practical significance to study the dynamic characteristics of the pile foundation on the slope and its influencing factors.The main contents of the work done in this thesis are as follows:(1)This thesis summarized the force characteristics and force analysis methods of pile foundations on slopes through data investigation,analyzed and compared different pile-soil interaction analysis models and seismic analysis methods.After comparison and selection,the use is limited.Meta-time history analysis was used as a numerical simulation method.(2)Combined with examples,after considering factors such as soil constitutive,pile-soil interaction and boundary conditions,a slope-pile three-dimensional finite element calculation model was established,and the calculation method was verified by comparing numerical analysis with physical experiments.(3)Under the above basis,several sets of seismic waves with different peak accelerations were used as dynamic loads,and the interaction between the pile foundation and the slope under the earthquake action was analyzed,and it is founded that the bridge pile foundation can reduce the dynamic response of the slope and enhance the stability;Due to the “slopeeffection”,the dynamic response of the bridge pile foundation is asymmetrical,the pile foundation on the side closer to the bridge has greater displacement response,and the pile foundation on the side closer to the slope has a greater internal force response;According to the law of pile acceleration amplification factor and pile height,the corresponding relationship function was established;The dynamic response of the pile foundation increases with the earthquake intensity It does not increase linearly,and the dynamic response increases rapidly when the earthquake reaches a peak acceleration of 0.4g.At this time,attention should be paid to strengthening the weak links of the structure such as the connection between the pile and the cap.(4)The influence of pile diameter,pile material modulus,anti-slide pile and different frequency spectrum seismic waves on the dynamic response of the pile foundation on the slope was studied by using the controlled variable method,and the results were analyzed,and the pile foundation on the slope was summarized.The diameter and modulus of pile have little influence on displacement,but will increase the internal force of pile foundation.Anti-slide pile can reduce the dynamic response of pile foundation.In this thesis,the reduction effect of the back row anti-slide pile is better than that of the front row anti-slide pile.Different seismic waves have different dynamic response due to different spectrum characteristics...