Dynamic Response And Reliability Analysis Of Retaining Wall For High-speed Railway

With the rapid development of high-speed railways,the high-speed trains have greatly reduced the travel time and resulted in remarkable economic achievements,which have further produced the changes in design requirements of railway track,embankment as well as the retaining structure.In the past decade,some attentions have been paid to the response of earth-retaining walls subjected to dynamic loads of high-speed train.Hence,this study focuses two research aspects:the dynamic response analysis of retaining wall of embankment subjected to dynamic loads of high-speed trains and the reliability analysis of the retaining wall considering the variability of soil parameters.Aiming at studying the dynamic response and assessing the reliability of retaining wall,the commercial finite element software PLAXIS 3D was utilized for finite element modeling of the entire geotechnical system.The software was used to evaluate the displacement and stress responses of the retaining wall under different train loads and train speeds ranging from 80km/h to 350km/h.Since the Chinese railway high-speed mostly uses the train speed higher than 160 km/h for passengers and the speed lower than 160 km/h is often used for freight trains,the 160 km/h speed designed for passengers is counted for as the minimum speed in this study.Under the dynamic loads of high-speed trains,the stability of the retaining wall was studied,and additionally,the reliability analysis of the retaining wall was performed by using the first-order second moment reliability method.Based on the research results,the following observations or conclusions can be attained:(1)The characteristics of dynamic loads were formulated to vary with the train speed.It was observed that the train speed more than 160 km/h takes a short time to pass over the railway track.(2)The numerical results indicate that,for the constant train speed and train axle load,the displacement response ot the retaining wall increases with the increase of the unit weight of soil embankment and decreases with the increase of the internal friction angle of soil.However,by varying the train axle loads,it is observed that the train speed higher than 160 km/h presented lower amplitude of lateral displacement response.(3)The numerical and reliability solutions showed that,by increasing the train axle loads the safety factor of the wall is small for the constant train speed of 160 km/h.Therefore,higher axle loads may affect the retaining wall by inducing large lateral displacement response,particularly those of railway track with poor quality of the soil.Furthermore,the increase of the train speed on the railway track,the safety factor of the retaining wall against sliding increases and higher reliability index can be observed.