Research On The Dynamic Characteristic Of Sand-Pile Evolvement And The Self-Organized Critical Phenomena

It is guessed that the emergence of self-organization criticality is depended on the size and structure principle of the system, the former foundation being experiments performed by Held, the latter still having not experimental evidence, and its theory explanation is still the blank space. The influence on self-organized criticality of the non-uniform of granular size is not taken into account in sand-pile experiments completed in the home and abroad, including computer simulation and real sand-pile experiment, and those experiments have been carried out only from the critical state, neither from the sub- critical state towards the critical state, nor in the critical state. It is discovered that self-organization criticality is related to the non-uniform coefficient of granular size in our water sand-pile experiments. Taking this as the gap, it is emphasized those respect work in our sand-pile model experiments, the dynamic characteristic of sand-pile evolution is analyzed, and some self-organization critical phenomena are researched as well.Main work and findings as follows:1 It is discovered in our sand-pile model experiments that, avalanches also obey to power-law distribution in the course of evaluation from the sub-critical state to the critical state, and sand-pile possesses the uncertainty in the critical state.2. Adopting the non- uniform difference sand,86 series in all, close to ten thousand wet sand-pile and dry sand-pile with one slope tests finished, it is confirmed the non- uniform of granular size affects the self-organization criticality.3. Adopting 2.5 -5 mm uniform sand and non- uniform sand of the non-uniform factor2.85, three kinds of compared experiments are carried out, including from the sub-critical state towards the critical state, in the critical state, and starting from the critical state as more;The dynamic characteristic of sand-pile evolvement, and the uncertainty and the complexity in critical state, are thoroughly analyzed; The forecast of large-scale avalanche in critical state is researched based on it. The understandings is obtained as follows:(l)Under little perturbation, two sand-pile spontaneously evolve towards the critical condition, yet presents two kinds of difference dynamics characteristic: large scale avalanche obeying quasi-cycle distributions for 2.5 - 5 mm sand-pile.and all scales avalanches obeying power-law distribution for the non- uniform factor 2.85 sand-pile. These two kinds of dynamics characteristic are confirmed with the phase space analysis means .(2)The reason of the two kinds of dynamics characteristic is that there are is two kinds of distinct forms of large-scale of avalanches in the critical state, keeping or diverging the critical state. Corresponding to these two kinds of dynamics characteristic, the critical state has two kinds of difference attractor types: fractal kinetics attractor and non-fractal kinetics attractor.(3) The two kinds of dynamic behavior are interpreted with the binary composition (the granular layer and the friction-resistance layer) model of sand-pile. It is thought that large-scale avalanches happen only in the granular layer in the critical state, keeping in the critical state, and all scale of avalanches obeying power-law distribution for the non-uniform factor 2.85 sand-pile. Whereas for 2.5-5 mm sand-pile, large-scale avalanches happen in the friction-resistance layer, diverging from the critical state ,then spontaneously evolve towards the critical state, large-scale avalanches happening in the critical state ,and small-scale avalanches in the sub-critical state, hence, large scale avalanche obeying quasi-cycle distributions. The relative density and direct shear characteristics are measured with the large-scale coarse grained soil test system, and it is discovered sand-pile of the non-uniform factor 2.85 much more close-grained ,and internal friction angle larger than2.5~5 mm sand-pile, hence the entire stability of the sand-pile can not been destroyed in the condition of our test, avalanches taking place...