| Self-organized criticality theory is in the forefront of the contemporary theory of nonlinear physics, which was put forward is to explain the disorder, the nonlinear behavior of complex systems. Sandpile model is the typical example of studying dynamical theory of self-organized criticality, and it can be seen as an interaction with the local area and wide space extension of the dissipative degrees of freedom dynamic system, a small disturbance will trigger the action of knock-on effect and lead to disaster. Therefore, on the basis of field research of the "5.12" Wenchuan earthquake disaster area, this article through the sand model centrifuge tests, using numerical simulation technology of particle flow method and three-dimensional discrete element method, under the framework of the concept of self-organized criticality theory, explained the landslide dynamiacal charactertics of sand model and slope under strong disturbance, and carried out a number of basic research work focuing on the landslide features such as the scale and scope of slope, for the railway, road slope at high intensity earthquake zone to provide scientific basis for prevention and control engineering. Major work and research findings are as follows:(1) The "5.12" Wenchuan Earthquake-induced secondary mountain hazards types, spatial distribution, influencing factors; the main characteristics were systematically analyzed and discussed. Main types of secondary mountain hazards are avalanches, debris flows and landslides, as well as they dammed lake formed by damming, as well as mudslides triggered by various kinds of disaster exists between the relationship of mutual transformation; secondary disasters, mainly along the Longmen Shan mountain earthquake fault zone and along the river flow was zonal distribution system into a linear distribution of the characteristics, distribution has obvious effects on the plate, the plate developed seismogenic fault density was significantly greater than the footwall. The secondary mountain hazards were controlled by the main factors of earthquake, but also by the tectonic fault, lithology, landforms, and other factors.(2) The article conducted a detailed investigation about landslide hazard of State Highway 213 from Dujiangyan to Yingxiu and Water Mill feeder. The landslide mode, landslide mechanism and landslide dynamiacal charactertics have been analyzed. Landslide disaster mode can be divided into rock slope landslide and bedrock and thick cover layer Landslide, which rock slope landslide include slump of landslides, landslides and falling rock three kinds of disaster mode; bedrock and thick cover layer landslide including the debris deposit, dilapidated and residual soil, accumulation landslide and diluvial deposit four kinds of disaster mode. Departure from the landslide scale and depth of slope, the law of landslide of slope show clear self-organized criticality dynamiacal charactertics.(3) On the basis of prophase sandpile experiment, based on quasi-static force method of thought, carried out three kinds of particle size grading of large-scale sandpile model experiments. According to principle of centrifugal test, the actual slope height reached 20.4m, more than all of the measure of the standard of sandpile model experiments carried ou at home and abroad. Experiments simulated landslide phenomenon of three kinds of particle size distribution sandpile under three kinds of disturbance intensity, disturbances of different intensity were achieved by changing the bottom slope angle, got three different dynamiacal charactertics of landslide:①0.5～1.0mm uniform particle sandpile, landslide scale show a quasi-periodic distribution when the inclination were changed 1.5°,3.0°and 6.0°;②8.0～10.0mm uniform sandpile and non-uniform sandpile ofΦ=3.10, landslide scale subject to a negative power-law distribution, showing self-organized critical landslide dynamiacal charactertics whenis the inclination were changed 1.5°;③8.0-10.0mm uniform sandpile and non-uniform sandpile of = 3.10, landslide scale show a normal distribution, when the inclination were changed 3.0°and 6.0°.(4) PFC2D numerical model was established based on the theory of granular flow and landslide scale of slope were studied under the action of strong disturbance. The numerical model analysised of the landslide scales of the same particle size distribution system under the action of different strong disturbing, and different particle size distribution system under the action of the same strong disturbing. The results showed that:the landslide scale of the same particle size distribution system, increased upward trend with the disturbance intensity to increase, but different particle size distribution system under the action of the same strong disturbing, reduced trend with the size of the particle to increase. Numerical simulation results with centrifuge model test results have good consistency.(5) The landslide failure processes were simulated under gravity by using three-dimensional discrete element method. The stiffness coefficient, time step, damping coefficient, friction coefficient etc. characteristic parameters to impact on landslide scope of slope were analysised. Calculation results show that:the friction coefficient is an important factor to slope stability, the deposit shapes of slope after failure has a very close relationship with cell size, the larger particle unit, the heap greater sphere of influence after failure; On the contrary, the smaller the unit, the heap smaller sphere of influence. At last, under the action of strong disturbance, the railway, road slope landslide prevention engineering should take into account the effects of gravity, while the collapse of falling rock should consider the impact of horizontal seismic force.(6) Finally, this article established a potential disaster assessment model of landslide scale of slope, and according to the model, the author completed the calculation and evaluation of typical landslides of Sichuan-Tibet road from Tongmai to 105 Maintenance under small, medium and large earthquake...
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