Shaking Table Test Study On Dynamic Response Of Different Density Accumulation Slopes

Anning River Fault Zone is located in the eastern margin of the Qinghai-Tibet Plateau,the seismic intensity in this area is high and the geological tectonic activity is strong,so the rock and soil mass here is weak and fragile,therefore,slope collapses and the accumulation of alluvial deposits in valleys often occur here,which forms a number of typical accumulation slopes.Strong geological effects often induce earthquakes and make the accumulation strongly deformed,and then lead to geological disasters such as landslides and debris flows.The study of dynamic response is the premise and foundation to ensure the safety and stability of slope structures in the earthquake-prone areas.At present,the study on the dynamic response of the accumulation body mostly focuses on the rock accumulation body,and the research direction mainly focuses on the influence of seismic characteristics such as amplitude,waveform,frequency or slope characteristics such as slope gradient,slope morphology,structure layer on the dynamic response,however,there are few studies on the dynamic response law of accumulation slopes under the condition of density variation.Hence,it is of significance to study the dynamic response law and failure deformation characteristics of slopes with different density of accumulation bodies under strong vibration.Based on the research of three sets of accumulation slope shaking table model tests with different densities,this paper had studied the distribution law of the model acceleration,dynamic shear strain,dynamic horizontal displacement during the test and the deformation and failure characteristics of the model,besides,the influence of amplitude,waveform and density on the dynamic response of the model had also been compared and analyzed.The main contents of the paper include:(1)This paper designed three sets of shaking table model tests of accumulation slopes with different densities,and according to the test requirements,completed the preparation of similar relationship design,boundary processing,model making,measuring point arrangement,loading scheme,etc.;Based on the results of the model tests,the position and trend of slope deformation were analyzed,and the failure morphology and movement characteristics of the accumulation slopes were summarized.(2)By setting a horizontal displacement meter on the slope surface and combining with the method that using the phosphor bronze strip inside the slope to measure the soil deformation,the deformation condition of the whole accumulation slope was grasped;The spatial distribution law of the response of acceleration,dynamic shear strain in the whole accumulation slope model was analyzed based on the analysis methods such as line charts and equipotential cloud maps.(3)On the basis of the shaking table model test results,this paper discussed the effects of amplitude,waveform and other parameters on the dynamic response of the accumulation slope using methods such as spectrum analysis,modal identification,control variate method,and comprehensive comparison,and the variation law of PGA amplification coefficient,dynamic shear strain and natural vibration frequency with parameters was emphatically discussed.(4)The effects of density changes on the dynamic response of the accumulation body were analyzed from three aspects: spatial effect,amplitude effect and waveform effect.The effect of density on the acceleration response depended on the relationship between the natural vibration frequency of the accumulation model and the spectrum distribution of the input wave;The effect of density on dynamic shear strain was mainly reflected in numerical value and position;The effect of density on the dynamic characteristics of soil is mainly due to the difference in the development of cumulative deformation of soil under different densities.