Dem Simulation Of Landslide Impacting On Bridge Pier And Dynamic Response Analysis Of Pier

With the increasing construction of bridges in mountainous areas in China,the risk of landslide,the most common mountain disaster,is also on the rise.Landslide impacting bridge piers and causing pier's crack,tilt or even collapse is one of the common destructive ways of bridge.In this dissertation,the debris landslide is taken as the main research object to explore the whole process and load characteristics on pier,and the response of pier under landslide load was analyzed.The main work and achievements are as follows:(1)The research status of relevant content at home and abroad was introduced.At present,there are relatively few literatures focusing on the impact of landslide on bridge piers and the response of piers.The main research objectives?objects and content were also illustrated.(2)The fundamental theory of particle discrete element method was introduced,and the discrete element model adopted in this paper was explained in detail.The contact parameters between particles were determined by a calibration test and can be used later.(3)The laboratory flume test was carried out and the corresponding discrete element model was established at the same time.The accuracy and reliability of the discrete element method and the validity of the contact parameters obtained before were proved by comparing the results of particle velocity,sliding morphylogy and normal impact force on the column.(4)Based on a simplified landslide model,20 discrete element models under different configurations were established to investigate the load characteristics of landslide impacting pier.The effect of landslide load on pier can be divided into impact and sedimentation actions.The slope has great influence on the landslide action.Landslide effect is mainly performed as the impact action when the slope is steep,and is mainly performed as the sedimentation action when the slope is slow.The slip distance has little effect on the landslide action,and the influence is different among different slope groups.The circular section pier can effectively reduce the force of landslide load and the bending moment produced.When the bridge pier is a certain distance from the foot of the slope,the landslide effect will be significantly reduced.(5)The finite element model of reinforced concrete pier was established.In order to simulate landslide load more realistically,the landslide load obtained by discrete element numerical simulation was applied in different regions.The displacement of pier top?the stress distribution of concrete and rebar were obtained.Then the results are compared with that of bridge in the construction.Finally,the possible failure modes of double-column bridge piers are studied by increasing the landslide load.