Experimental Study On Dynamic Response And Instability Mechanism Of Steep Dip Bedding Slope By Centrifuge Shaking Table Model Test

China is situated between the circum Pacific seismic belt and the Mediterranean Himalaya earthquake belt.It is the largest continental seismic area in the world and also a country with frequent earthquakes.In the steep and steep mountainous areas of Western China,earthquakes will cause high and steep slopes to be unstable,and induce secondary geological disasters such as collapse,landslide and debris flow.In May 12,2008,the Wenchuan earthquake caused numerous landslides,landslides and other geological disasters,which caused catastrophic damage to the epicentral area and its surrounding areas.In the investigation of secondary geological hazards induced by the Wenchuan earthquake,a large number of steep slopes are found to be unstable,which is inconsistent with the traditional "steep slope".This kind of slope is unstable under the action of strong earthquake.Only by studying the instability mechanism and dynamic response law of steep dip bedding slope under strong earthquake can the problem be clarified.Based on the "5.12 Wenchuan earthquake" as the research background,through to the Wenchuan earthquake region of steep bedding slope instability characteristics,based on the field investigation and analysis,a conceptual model is established.Combined with the test method of centrifugal vibration analysis of steep bedding slope dynamic response characteristics and failure mechanism,the main work and results the following:(1)According to a large number of field investigation of Wenchuan earthquake induced by steep inclined bedding slope dynamic instability as an example,the typical dry mill landslide and Dazhu Ping landslide as an example,the abstract generalized layered hard rock and soft and hard interbedded with two different slope structures of steep bedding slope.(2)According to the basic principle of dynamic centrifuge model test and similar dimension analysis principle to determine the similarity constants of model test,the model of slope of hard rock and soft rock material and ratio test,through the selection of optimal model test of similar materials and the corresponding proportion,and according to the selected measurement test the corresponding components and the design to the arrangement of testing points,according to the test to determine the loading scheme of seismic wave.Based on the design and implementation of the whole experiment,a complete set of test method for the dynamic centrifuge model test of steep dip bedding slope is established.(3)The geotechnical centrifuge carried out steep centrifugal shaking table model test of bedding slope,with high-speed camera and monitor system observation two slope deformation characteristics of the model,and then analyzes the evolution process of slope deformation,and the analysis of steep bedding slope instability mechanism.The analysis shows that the steep dip bedded hard rock slope is dominated by collapse and slope shoulder rock mass,while the main failure mode of soft and hard interbedded slopes is slip bending.(4)Comparative analysis of the acceleration data of layered hard rock slopes and interbed slopes in different earthquake loading monitoring,discusses the ground motion parameters and its slope geological conditions on steep slope along the influence of layer seismic dynamic response.Considering the impact of various factors on seismic dynamic response of slopes,analysis of the power law and different slope structure dynamic response of slope steep bedding slope level amplification,elevation amplification effect,surface effect,different amplitude condition of slope response law.The dynamic response analysis results reveal the deformation and failure characteristics and instability mechanism of steep dip bedding slope under earthquake action.(5)By three-dimensional discrete element software 3DEC inversion of steep bedding slope failure forms,based on the analysis of the failure modes of layered hard rock and soft and hard interbedded slope slope under seismic load,and the centrifugal shaking table model test results.The results show that the numerical calculation and the centrifugal shaking table model test of slope failure characteristics are basically consistent with each other,thus,the numerical simulation basically reflected the whole failure process of steep bedding slope centrifugal shaking table model test of slope and the instability mechanism.