Test Study And Numerical Analysis On Dynamic Response Of Block Reinforced Soil Retaining Walls

The two-stage reinforced soil-retaining wall was damaged in Wenchuan earthquake and the existing modular vertical reinforced retaining wall,were taken as the research object.Two large shaking table tests were designed and completed;The numerical model of reinforced soil-retaining wall was established by FLAC3 D software,and the test condition of shaking table was simulated;According to the test results,national standards and other research results of experts and scholars,the potential rupture surface of two-stage reinforced soil-retaining wall at this stage was summarized.The main tasks were as follows:(1)According to the similarity theory,the similarity relations of 17 independent physical quantities were derived by using method for dimensional analysis.The similarity relation of model test was determined;A two-stage reinforced soil-retaining wall model with a similar ratio of 1:10 and a single stage reinforced soil-retaining wall model with a similar ratio of 1:4 and a similar ratio of 1:2 had been established.The model packing,geogrid,model brick,sensor type and placement position were determined,and the basic situation of materials was introduced.The type of input seismic wave and the experimental loading scheme were determined.(2)The dynamic characteristics of the model under horizontal earthquake were studied by shaking table test of two-stage reinforced soil-retaining wall: The macroscopic phenomena of retaining wall and the failure mode of retaining wall under various working conditions were observed;The acceleration response at different height and position of the model were tested;the displacement response and remanant displacement response at different position of retaining wall were tested;The distribution of dynamic earth pressure at upper and lower retaining walls and steps were studied;The strain distribution of geogrid were studied.(3)The dynamic characteristics of the model under horizontal earthquake were studied by shaking table test of single stage reinforced soil-retaining wall: The macroscopic phenomena of retaining wall and the failure mode of retaining wall under various working conditions were observed;The acceleration response of the model at different similarity ratios,different heights and different positions were tested and the spectrum characteristics of the model were analyzed;The displacement response and remanant displacement response of different similarity ratio,different position of retaining wall were tested;The responses of settlement distribution and remanant settlement distribution of the retaining wall at different top positions under different similarity ratios were tested;The distribution of dynamic earth pressure of retaining wall under different similarity ratios was studied;The strain distribution of geogrid under different similarity ratios is studied.(4)The numerical model of two-stage reinforced soil-retaining wall and single stage reinforced soil-retaining wall were established by using FLAC3 D.And imposed the test conditions consistent with the shaking table test.The response of the acceleration,the dynamic displacement,the vertical settlement,the dynamic earth pressure and the stress of the reinforced material under the horizontal earthquake was studied.(5)This paper introduces four kinds of calculating methods of potential fracture surface at present.Applied mathematical method,the exponential fitting of all working conditions under the action of Wolong wave and EL-Centro wave was carried out.Based on the calculation methods of all kinds of potential rupture surface,a double broken line model considering the width of the offset was proposed,which can be used as reference for design and calculation of reinforcement length of two-stage reinforced soil-retaining wall.