Study On Seismic Dynamic Characters Of Rock Slopes And System Including Formation Mechanism Of Landslides, Stability Discrimination Of Slope And Assement Of Harzard Scope Of Landslidefor Slope Of Bedrock And Overburden Layer

Researching on the dynamic stability of slope subjected to earthquake is an important project in geotechnical engineering field. However, the engineering geology, soil mechanical, geophysics, and earthquake engineering is involved in this project, which is very difficult, and now there are many problems which must be overcome. Both the special geographical conditions and geologic structures determine that the problem of seismic stability of slope is very conspicuous in China. However, the infrastructures in our Country is basking in a great boom such as road, railway and water conservancy, which needs higher demands for the seismic design of slopes and the hazard assessments for landslides, and the existing theories and practices can’ t satisfy this need. Therefore, researching on the seismic stability of slopes is very important, which is useful to reduce the hazards caused by the landslides as soon as possible, produces a favorable living environment for the people living in the mountain area, and ensure the normal and safety operation of the geological engineering facilities.Based on the simply review of seismic stability of slopes and the background of Wenchuan earthquake, aiming at the related science problems existing in the current phase, following the dynamic characteristics of slopes subjected to the earthquake, using the methods such as the field investigation, numerical analysis, shaking table test, the monitoring data of the seismic array and the theoretical derivation, taking the covering layer- bedrock type slope which is destroyed seriously, this project reveals that dynamic characteristics of the rock slope, and analysis the formation mechanisms of the landslides, and then proposes the assessing system of the landslide hazards and a method which can consider the three factors of earthquake wave which are duration, amplitude and frequency, respectively.First, using the large shaking table test, numerical simulation and the field results of seismic arrays, this paper analysis on the impacts of the factors such as the slope angle, seismic intensity, the type of the seismic wave, slope type and local topography on the seismic characteristics. And then, based on the elastic wave theory, combining with the results of the shaking table test and numerical simulation, this paper derives the theory solutions of seismic responses of the rock slope with two-side slopes, which can reveals the dynamic characteristics in the point view of quantitative calculations.Second, based on the research results of the dynamic characteristics of slopes, combining with the results of shaking table test and numerical simulation, taking the covering layer-bedrock as the object, generalizing the analysis model, this paper uses the new time-frequency-amplitude analysis skills and researches on the deformation characteristics of slope and the landslide formed mechanism from the time domain, frequency domain and time-frequency domain.Third, the shortages of using pseudo-static method to assess the seismic stability of slopes have been recognized by the public widely with the depth understanding of the dynamic stability problem of slopes. And then, the time-frequency analysis method has been the developing tendency of the seismic designs of slope engineering. Based on the elastic wave theory and generalized analysis model, this paper proposes the time-frequency method using Hilbert-Huang transform, and the validity of this method has been verified by the results of shaking table test and numerical simulation.Fourth, the effective method treating the large and widely distributed landslides occurred by earthquake in the nation’s infrastructures and the post-disaster reconstructions is considering the issue of landslides in the planning stage. In other words, assessing the harmful of landslides using the prediction model based on the related parameters after the assessment of the seismic stability of slopes. For a long time, the major run-out distances prediction models of landslides only consider the volume of landslides and the most vertical run-out distances. However, the major research results indicate that the peak ground accelerations (PGA) and the slope angle have a good correlation with the distribution and scale of landslides. Therefore, based on the field investigation results, this paper uses the attention model of PGA, and establishes the horizontal run-out distance of landslides which can considers the factors such as the height of mountain HL, slope angle θ, the peak ground acceleration (PGA) and the volume of landslides.