饱和散体的分形行为与振动液化

饱和散体结构复杂, 在振动作用下会发生液化现象。利用分形几何学分析得出散体粒度分布、孔隙分布和颗粒比表面积都具有分形特征, 服从标度律。振动过程中, 时间序列、功率谱密度、振动脉冲积分分布、时间序列的自相关函数均服从幂律关系,具有分形特征。振动液化的稳态发展过程服从幂律, 在振动过程中显示出自组织临界性, 随着循环次数达到一定程度, 饱和散体应力急剧减小或完全丧失, 应变急剧增加, 已不能再承受荷载, 出现“雪崩” 现象。

Fractals and Vibrating Liquefaction of Saturated Granules

Saturated granules have a complicated structure and liquefaction will take place by the effect of vibration. The authors analyse their size distribution, pore distribution and specific surface area by means of fractal geometry, coming to the conclusion that they all have fractal characteristics and obey the scaling law. In the course of vibration, time series, power spectral density, integral distribution of vibration pulse and autocorrelation functions of time series all obey the power law and have fractal characteristics. The steady development process of vibration liqufaction obeys the power law. In the course of vibration, self-organizing criticality is displayed. With increasing recurrence number the stress of saturated granules will decrease or disappear completely and the strain will ncrease rapidly, so that the granules can not sustain load, resulting to "avalanche".