Dynamic Analysis Of Flexible Cantilever Retaining Walls By A Modified Vlasov Model

As common retaining structures, retaining walls are widely used in civil construction, bridge engineering, highway engineering, water port engineering and railway engineering. Located in the world's two seismic zones- between the circum-Pacific seismic zone and the Eurasian seismic zone, China is a earthquake-prone country. According to earthquake damage survey, it is found that the destruction is widely existed in retaining wall in strong earthquakes. Therefore, the seismic design of retaining walls is very important in earthquake structural engineering and is highlighted by researchers from various countries. The Mononobe-Okabe method for seismic design of retaining walls is a common method to calculate earth pressure, but this method does not consider the interaction between the soil and retaining walls, and is more used in the seismic design of rigid retaining walls.Dynamic response of a flexible cantilever wall retaining elastic to harmonic transverse seismic excitations is determined with the aid of a modified Vlasov foundation model. Two cases of walls fixed at the base and elastically constrained against rotation at the base are studied, respectively.Firstly, on the assumption of vanishing vertical displacement of the soil medium, a novel displacement model about the soil-wall interaction to harmonic transverse seismic excitations is proposed, respectively. Secondly, according to the Hamilton's principle, the free-field displacement can be solved. Moreover, when considering the soil-wall interaction, the governing equations and boundary conditions for the unknown displacement and attenuation functions in the model can be obtained, and the functions are coupled each other. Thirdly, solutions of the two unknown coupled functions are obtained on the basis of an iterative algorithm. Meanwhile, the present approach is verified by comparing its results with those of the existing analytical solution. At last, a parametric study is performed to investigate the effects of the soil-wall system properties and the excitations on the dynamic response of the wall. The results of the analysis reveal that, to horizontal earthquake excitation, wall flexibility, incident frequency and the constraint conditions of retaining wall are significant.The major contribution of this study is:(1)A novel displacement model is proposed for the soil-wall system, respectively;(2)The analytical solutions is obtained based on the Modified Vlasov model;(3)A physical model of great significance is abstracted from the present method, respectively, and based on Veletsos and Younan model, a membrane connecting a series of springs simulating the continuity of the retained soil is raised. And the explicit expressions of the equivalent Winkler modulus and the membrane are also obtained.