Dynamic Response Characteristics And Evolution Law Of Deformation Instability Of Loess Slope With Fissures Under Strong Earthquake

The Loess Plateau is one of the major areas with frequent occurrence of strong earthquakes and frequent geological disasters in China.In the past,strong earthquakes caused more than 1.4 million deaths in the area.The earthquake caused a series of landslides(walking mountains)to bury towns and villages,which is the main cause of huge casualties.In view of the current situation of wide,frequent and heavy geological hazards in the Loess Plateau and accordingly it is of great practical and scientific significance to study the occurrence and evolution mechanism of loess slope deformation instability under strong earthquakes.In this paper,the fractured slopes of typical loess yuan in Kongtong District,Pingliang City,Gansu Province are studied.Combined with large-scale shaking table model test and particle flow discrete element numerical simulation method,the dynamic response characteristics of typical loess slopes under different seismic loads are studied.The main research work and conclusions of the instability evolution process are as follows:(1)Concluding failure types and deformation characteristics of slope seismic instability in Loess Plateau;Analysising the geomorphological features,geological structures and hydrogeological conditions of the Pingliang City,Gansu Province and studying representative slopes of loess yuan.(2)A comparative shaking table model test with fractured loess slopes and crack-free loess slopes was designed and developed.According to the similarity constant of model test using similarity theorem and the mixture ratio of similar materials determined by laboratory tests,the slope model was made and the monitoring components needed for the experiment were selected.The Wenchuan earthquake soup wave and El Centro wave were used to load different directions and intensity.(3)By processing,comparing and analyzing the collected seismic dynamic response(displacement,acceleration,pressure)data,the seismic loading effects of displacement,acceleration and earth pressure response in different directions and intensities are obtained at different positions of the fractured loess slope and the non-fractured loess slope.Then,the dynamic response characteristics of the two types of slopes under strong earthquakes are analyzed and summarized.(4)In order to further study the discontinuous phenomena such as fracture propagation and failure inside the slope and supplement the deficiency of shaking table model test,the evolution law of deformation and instability of this typical loess slope under earthquake action is revealed by using particle flow discrete element numerical analysis method...