Research On Static And Dynamic Bearing Performance And Geogrid Lateral Limit Creep Characteristics Of Reinforced Earth Retaining Wall

Geosynthetic reinforced materials are widely used in reinforced soil retaining walls,slopes,embankments and other engineering fields.At present,the research on the bearing capacity and failure mode of geogrid reinforced soil retaining walls is mainly based on static load.The bearer failure mechanism at the time of dynamic loading still lacks sufficient knowledge.In this paper,with the title of "Research on Static and Dynamic Bearing Performance and Geogrid Lateral Limit Creep Characteristics of Reinforced Earth Retaining Wall",the test of the retaining wall of reinforced soil abutment under static and dynamic loads and the creep test of geogrid under confined or unconfined condition are carried out.The design and construction method of reinforced earth retaining wall with or without confined creeping is discussed.In the indoor model test of the reinforced earth abutment retaining wall,the river sand is used as the retaining wall filler,the geogrid used as the reinforced material,and the static and dynamic loads are applied by the MTS servo loading system to carry out the static and dynamic loads model test of the geogrid-reinforced soil abutment retaining wallswith 16 working conditions.The influence of different laying methods,length of reinforcement,type of geogrid,loading plate position,load level and number of cycles on the bearing capacity of reinforced earth retaining walls are analyzed.The influence of the offset distance of strip foundation on the ultimate bearing capacity of the foundation is studied,and the bearing performance and failure mechanism of the reinforced retaining wall under static and dynamic loads are revealed.The indoor tensile creep test under confined or unconfined conditions was carried out separately.The creep properties of geogrids with different load levels with or without confined conditions are analyzed,and the creep curves and load-strain isochron curves of geogrids with or without lateral constraints are further studied.The creep formula of the reinforcement under the confined constraint condition is proposed,and the creep model of reinforcement in reinforced soil structure is discussed.Based on the indoor model test and the design requirements of the stability of the reinforced earth retaining wall model,the GEO5 geotechnical design software is used to analyze and calculate the creep reduction factor of the reinforced soil retaining wall under different working conditions.The geogrid creep reduction factor under the condition of presence or absence of the limit respectivelyis 2.40~1.90 and 3.0~2.60,which is smaller than the creep reduction coefficient given by American code(FHWA)for different types of polymers.