| “5.12”Wenchuan earthquake produced a large number of landslides which brought a huge disaster to the people in the disaster area,causing extremely heavy casualties and incalculable economic losses.According to the survey,the geological condition's commonness of rock landslide which triggered by Wenchuan earthquake is that the mountain has characteristics of layered cataclastic structure and very well developed joints,especially along the bedding cataclastic rock slope,is easy to trigger the landslide under earthquake effect.Therefore,the study of bedding cataclastic rock slope is of great significance and extremely urgent.Taking down pour of layered rock slope is cataclastic structure as the main research object,and around the seismic dynamic response rules and the mechanism of instability of subject,combined with the shaking table test,theoretical research,numerical simulation of three kinds of research methods,at the wolong road to yingxiu-K24 landslide engineering as an example,the down pour of layered rock slope is cataclastic structure in different intensity of structural plane under the action of earthquake dynamic response rules of,failure mechanism and failure mode characteristic has carried on the system and in-depth research,the main research results and the content is as follows:(1)Take the Wolong road to Yingxiu K24 landslide slope engineering example as the prototype,designed three different structural plane strength parameters of rock slope model,and formulate the corresponding vibration table test plan,including identifying model can satisfy the similar than the optimal mixture ratio of cementing material,determine the boundary conditions of test model,test equipment and test system arrangement,the slope model design,sensor installation and debugging,the selection of input earthquake wave including wolong wave interception process,the rest of the natural seismic wave and sine wave loading scheme,according to the working condition of each load,key record slope model of acceleration time history data and signs of damage.(2)The shaking table test results were collected and analyzed,and the influence of structural plane strength on the horizontal and vertical seismic dynamic response of the slope was emphatic studied.Results show that the level of dynamic response characteristics of the slope model has obvious high table effect,the intensity of structural plane of horizontal dynamic response has a great influence,under seismic effect,the level of PGA amplification coefficient increases with the reduction in the intensity of structural plane and slope,under the effect of earthquakes and earthquake,the level of PGA amplification coefficient with reduced with the decrease of the intensity of structural plane of the slope;The greater the intensity of the structural plane,the greater the correlation between the vertical PGA amplification coefficient and the amplitude of the input wave,that is,the more obvious the property that the vertical PGA amplification coefficient increases with the amplitude.(3)Based on the shaking table model damage phenomenon,summarizes the two failure modes:"crack extension-integral sliding failure mode"and"crack extension-as a whole to pieces failure mode",based on the analysis of two kinds of failure mode,structure of the slope body strength can play a very important influence on the slope failure model,the stronger the intensity of structural plane of slope body,the slope failure pattern in a more overall from the parent rock rigidity,thus forming order type failure surface;The weaker the strength of the slope structural plane,the more likely the slope is to be unstable,and the failure mode collapses in the form of quasi-flow state,forming a new slope with a more smooth and broad surface.(4)Based on the principle of fracture mechanics and the theory of elasticity,the instability failure mechanism of bedding cataclastic structure rock slope under earthquake is studied in depth.Analyzed the geometry and stress conditions of initial crack extension,deduces the calculating formula of the initial crack Angle of the most dangerous,on the basis of the simplification of rupture surface,is deduced under the action of horizontal seismic landslide after the formula of the critical edge crack propagation of earthquake acceleration,and based on the landslide margin fault zone under the condition of complete be well versed in,after considering clinical impact effect,the peak residual strength drop effect and wave oscillation effect to shun pour the role of layered rock slope failure,and by using the theoretical formula for startup donghekou landslide and concrete analysis of the influence factors of the K24 landslide starts.(5)Using UDEC to carry out numerical simulation of K24 landslide,the influence of structural plane strength on acceleration,velocity and displacement dynamic response of slope is mainly studied according to the simulation results.The results show that the lower the strength of the structural plane,the faster the PGA amplification coefficient increases in the horizontal and vertical directions in the elevation section near the top of the slope.When the normal stiffness and tangential stiffness are reduced to 2GPa·m-1,the landslide starting speed and permanent displacement increase dramatically.In addition,two failure modes of K24 landslide on Yingxiu-Wulong Highway under different structural plane strength are summarized:“initial slope displacement-horizontal ground fragmentation-slope toe warping failure-sliding body toppling failure mode”and“initial slope displacement-horizontal ground vibration-slope toe extrusion failure-sliding body collapse failure mode”. |
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