Test Study And Numerical Analysis On Seismic Response Of Two-step Cantilever Retaining Walls

Two-step cantilevered retaining wall by a single-step L-shaped cantilever retaining wallgoes to the next puzzle mode stack consisting of a single-step cantilevered upper L-shapedretaining wall and lower single-step L-shaped cantilever retaining wall, the structure type issimple, occupies area little，and less demanding on the foundation bearing capacity and so onother characteristics, it has gradually been applied for the project. Currently, the design ofretaining structures is still in exploring, the experience is ahead of the theory, especiallydynamic response under seismic loads is very lacking in abroad. However, from largeearthquake engineering practice in recent years shows that when designing, theground-breaking pressure role in retaining structures by only considering quasi-staticapproach has large differences with that under actual seismic loads, and the distribution formsalso are not the same.Therefore, the dynamic characteristics study of Crib cantilever retainingstructure under seismic loads is very important and meaningful.Based on research results of the various types of retaining walls in dynamiccharacteristics, This article takes the two-step cantilevered retaining wall as the study goals,uses analytic method and indoor shaking table test as well as numerical calculation methods,more systematically analyzes the influence of the main factors such as the backfill materials,wall level, wall height on seismic performance of the two-step cantilevered retaining wall.this paper studies the main contents, the method and the corresponding results as follows:(1) Access to relevant literature, summarizing the form and analysis methods (analyticalmethod, numerical methods, test methods and field test methods) of the earthquake damageof existing cantilevered retaining wall, and has a summation for an indoor model test results,inducting the impact of various factors in model test on the seismic performance of cantileverretaining wall,which provides the reference value for shaking table model experimental andthe numerical analysis of dynamic characteristics of the two-step cantilevered retaining wall.(2) Based on the similarity theory, using dimensional analysis to determine the similaritycoefficient of indoor model test, produced six groups of cantilevered retaining wall model,carrying out vibration tests at different levels of seismic acceleration peak, testing acceleration,lateral relative displacement and variation regality of lateral earth pressure with wall heightof the two-step cantilevered retaining wall model, analyzing the affect of the three factorssuch as retaining wall filler type, grade and height seismic performance of cantilever retainingwall, and comparatively analyzing test results of a single-stage cantilever retaining wall.(3) Establish a two-step cantilevered retaining wall dynamic model. This paper adoptsMIDAS/GTS finite element software to analyze the characteristic of retaining wall under thedifferent peak ground acceleration in order to research the its acceleration, relative displacement as well as distribution rule of dynamic response. Thus it could be comparedwith experiment results indoor and provide reference value to design and construction ofretaining wall.(4) Propose the calculation methods for two-step cantilever retaining wall. On one hand,this paper considered the grading wall condition, on the other hand, it assumed the whole wallcondition. As for different type of wall, wall height, retaining grading and peak value ofseismic acceleration, it compared the results between model tests and numerical simulations,following which referred to the pressure correction coefficient under different seismiccondition and the application and advantages of Two-step cantilevered retaining wall that inreturn provided application theories and technology reference.