Research On Dynamic Response Of High Rock Slope And Its Application

The ways to analyze dynamic stability problem of rock slope can be classified as pseudo-static methods and numerical simulation methods. Although the achievements of Pseudo-static methods are abundant and theoretical systems matured, it still has many obvious defects. Meanwhile, it became a researching obstacle that aroused many attentions of the scholars because people using dynamic FEM to analyze dynamic time history problems are only a few and achievements even lesser, especially after the disastrous earthquake of WenChuang. It becomes a widely concerned and also urgently to be solved problem in both geotechnical and geological field to solve the dynamic response regulation of rock slope in horizontal dynamic loads.The researching status concerning dynamic problems of rock slope is summarized, the factors especially from engineering geology aspects that would affect the stability of rock slopes under seismic loads are analysed, the procedure to conduct on FEM analysis and the ways of solving dynamic equation problems are summarized and analyzed. It is also discussed in this article the dynamic response regulation of rock slope using FEM, much more important is the discussion of the regional dispatching rules and features of the three magnification factors such as displacement, velocity and acceleration under horizontal dynamic loads. Some important results and conclusions are as follows:(1) On the basis of previous achievements, the influence factor of slope stability under seismic loads is classifed as geological background, combination of the structure of rock slope and rock mass properties, conditions of terrain and landform and hydrogeology condition. The engineering geological model and dynamic instability mechanism have also been discussed.(2) The procedure of conducting FEM and the methods to solve dynamic equation problems is summarized and analyzed. Dynamic equation and computing methods, nonlinear dynamic equation and calculation methods, element type employed in a slope stability analysis under seismic loads and D-P elastoplastic constitutive relations and yield criterion are also discussed. (3) The influence patten of viscoelasticity boundary elements and Rayleigh damping under dynamic equation of rock slope are discussed. The following research had been done:①The influence of boundary setting is discussed. It turns out that when viscoelastic boundary parameters are properly chosen and a certain distance from the boundary kept, boundary has little effect on calculation results.②The influence of Rayleigh damping is discussed, it turns out that Rayleigh damping has a prominent influence on the results.③The influence of D-P elastoplastic constitutive relations and yield criterion is discussed. When D-P has been used in material, the magnification factors are less than linear elastic one.④When elastic modulus of material is reduced, the magnification factors increased.⑤The duration time, frequency and amplitude of loads affects the magnification factors a lot.(4) The dynamic response of a rock slope in southwestern China under seismic loads are analyzed, and some useful conclusions derived. Viscoelasticity boundary elements which are used in simulation of rock slopes of dynamic response.The magnification factors are less when D-P is used and when the displacements are few, D-P take a little effection on magnification factors. Proportion modification in EL-Centro earthquake waves, 0.1g, 0.12g, 0.15g and 0.2g are choosen in bedrock peak acceleration. When 0.1g and 0.12g are choosen, the whole slope is in elastic state and magnification factors are closed.When there are small regions in plastic which are not important when 0.15g is choosen. So parts of parameters are modified and the whole slope is still in elastic, magnification factors are closed in results. Unloading cracks is in huge displacement and it is instability and some reinforcement measures are advised.