| This paper focus on the study on the self-organized criticality (SOC) in large-scale non-uniform granular mixtures, and the mechanical reasons of SOC, as well as the application of SOC in granular mixtures. The main findings are as follows:1. Firstly, based on the experiment of large-scale critical slope made up of dry sand-gravel mixtures, which was disturbed by a sand adding convey from the top of the slope, it is confirmed that self-organized criticality in granular mixtures is strongly influenced by the non-uniform degree of granular material. The non-uniform degree, as organizing structure principle, is a universe factor which affecting SOC. Then, using the large-scale coarse grained soil test system, the relative density and direct shear characteristics of sand-gravel mixtures in different size distribution were tested. And the SOC affecting mechanism derived from non-uniform granular material was discussed. The phenomenon can be observed that, along with the increase of non-uniform degree, the accumulate structure will become more complex, and the sliding resistance among sands will grow accordingly. The physical characters determined by the structure of non-uniform granular mixtures, the multiform failure states and the higher energy dissipation, can cause sufficient restraint on disturbing-feedback propagation, granular mixtures will maintain overall stabilization accordingly. Thus, the two dynamical conditions (sensitive and robustness) will be satisfied simultaneously, And a large-scale non-uniform granular mixtures system can show the SOC as well.2. By means of the improved phrase space reconstruction method, the sand-falling series of the large-scale critical slope experiment were analyzed. It was discussed on the situations of different non-uniform degree and different disturbing intensity. In this paper, the approach for calculating intercalation dimension of attractors had improved. Information in sand-falling series will be well reserved correspondingly, the attractor's structure in different distance space will be comparable, and calculating precision will improve, especially in shortseries situation. The primary conclusions can be drawn: the intercalation dimension estimate value and Kolmogrov entropy of grading uniform degree sand-pile which present SOC are larger than non-uniform sand-pile. And if disturbing enhanced, the intercalation dimension estimate value and Kolmogrov entropy will rise too.3. Utilizing the three-dimension self-similar percolation model, the paper probed into the renormalization group method of grid of non-uniform granular mixtures, and the relationship between stabilization and non-uniform degree was discussed. It is put forward that, taking rational microcosmic connection rule judgment into account is very important. In view of the percentage of void in natural deposit, it is deemed that the increased self-similar rank M can enhance the stability accordingly. And the pattern of stabilization will be non-linear characteristic. Through studying the critical index, there is a strong changing characteristic of correlation length.4. The non-linear interaction mechanism derived from the scale of system was discussed. The paper deemed that, falling sliding face is not a rectilinear type, the non-linear coupling of falling factors sharply enhanced in large sand-pile; the stabilization of surface layer sands are different in the time and space, especially the stating probability is higher than halting, and probability of fault in slope foot is higher than top as well; the faulting forms will be affected by bounder situation strongly.5. By the phenomenon came from critical sand-gravel granular mixtures slope experiment, the falling causation, form, scale, and preventing principal in sliding-sand slope were discussed. The causation can be drawn: the slope received sands from the slope top continuously; non-uniform degree and granular size in strong weathering environment may be changing; and the restrain in slope foot was weakened. These factors, cau... |
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