基于分形理论的北京地区砂砾石地层细观建模

发布时间：2018-05-27 00:43

本文选题：土力学 + 砂砾石地层　；参考：《岩石力学与工程学报》2017年02期

【摘要】：土石混合体材料及相应地层中地下结构的力学行为及变形规律受到颗粒粒度组成与分布规律的影响。采用分形几何学对土石混合体的粒度分布进行描述,进一步明确了质量粒径级配曲线与粒度分形维数之间的关系。在双对数坐标系Tlg(M(rR)M)-lg R下对34组砂砾石土进行粒度分形,结果表明:北京地区砂砾石土粒度分布满足分形结构,其粒度分维区间值为2.4~2.6。根据统计的粒度分维区间,分析了颗粒级配随分形维数及最大粒径的变化规律,对土石混合体的力学性质及稳定性给出了新的认识。并将分形理论与室内试验颗粒级配分布结合,反演出土石混合体完整的颗粒级配分布。基于Monte-Carlo原理,结合分形理论,采用圆形或球体表征块石的形状,编写砂砾石地层模型生成程序,建立砂砾石地层模型,并针对隧道的开挖问题展开了数值分析。
[Abstract]:The mechanical behavior and deformation of soil and rock mixed materials and underground structures are affected by particle size composition and distribution. The particle size distribution of soil-rock mixture is described by fractal geometry, and the relationship between particle size distribution curve and fractal dimension of particle size is further clarified. In the dual logarithmic coordinate system (Tlg(M(rR)M)-lg R), the particle size distribution of 34 groups of sandy gravel soils is fractal. The results show that the grain size distribution of Beijing sandy gravel soil satisfies the fractal structure, and the fractal dimension of grain size is 2.4 ~ 2.6. According to the statistical fractal dimension of particle size, the variation of particle gradation with fractal dimension and maximum particle size is analyzed, and a new understanding of the mechanical properties and stability of soil-rock mixture is given. The fractal theory is combined with the particle gradation distribution in laboratory test to reverse the complete particle gradation distribution of soil-rock mixture. Based on Monte-Carlo principle and fractal theory, the shape of block stone is represented by circle or ball, and the program of sand gravel formation model generation is compiled, and the sand gravel stratum model is established, and the numerical analysis is carried out in view of the excavation problem of tunnel.
【作者单位】：北京工业大学城市与工程安全减灾教育部重点实验室;
【基金】：国家自然科学基金重点项目(51538001) 北京市自然科学基金重点项目(8161001)~~
【分类号】：TU43

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