散粒体离心模型自组织临界性及地震效应分析

基于自组织临界性(SOC)理论,运用土工离心模型试验技术,开展了粒径为0.5～1.0 mm的均匀沙和非均匀系数φ=3.1的非均匀沙两种级配的散粒体沙堆模型试验。并在试验基础上分析了散粒体斜坡崩滑地质灾害的SOC现象和地震诱发作用下散粒体斜坡崩滑失稳的模式与规律。研究结果表明,大尺度松散堆积散粒体系统在一定条件下也能呈现SOC现象,体现了以土木工程为背景的散粒体斜坡崩滑地质灾害规律,突破了关于SOC研究的尺寸效应问题;同时该沙堆模型离心试验还模拟了在拟静力水平地震力作用下散粒体斜坡崩滑的失稳模式,提出了在相当于地震烈度为Ⅴ度的拟静力水平地震力诱发作用下,φ=3.1的非均匀沙石散粒体系统崩滑失稳符合幂律分布,呈现SOC的结论。

Analysis of self-organized criticality of centrifugal model tests on granular mixtures and earthquake effect

A sand dune with one slope was used as the simplied pattern of a loose slope.Two groups of centrifugal model tests on uniform sand with the sorting coefficient φ=1 and non-uniform sand with the sorting coefficient φ=3.10 were reported.Based on the theory of self-organized criticality(SOC),the SOC phenomenon of landslides and avalanches of loose slopes were analyzed by centrifugal model tests on sand dune.It was indicated that large-scale loose granular mixtures systems exhibited also SOC phenomenon with scale effect.Furthermore,this centrifugal model tests on sand-piles also simulated the modes of the landslides and avalanches of loose slopes induced by earthquakes.It could be concluded from the centrifugal model test results that the landslides and avalanches of loose slopes induced by earthquakes conformed to power formula.