土石混合体压缩性的三维颗粒力学研究

3-D granular simulation for compressibility of soil-aggregate mixture

土石混合体是由作为骨料的砾石或卵石与作为填充料的黏土或砂土组成的特殊工程地质材料,无论天然形成或人工合成,其力学特性与均质土体或岩体相比均有较大差异。以昆明新机场高填方中大量采用土石混合体填料为工程背景,在三维颗粒流程序中对特定的土石混合体试样的侧限压缩试验进行数值模拟,比较了不同级配条件下土石混合体模型的微观结构及基本力学物理性能。通过比较侧限压缩模量和压缩后孔隙率,研究了含石率对土石混合体骨架效应等结构性的影响,并提出了工程中建议采用的土石比例区间,在颗粒流方法用于实际工程方面进行了有益的探索。

Soil-aggregate mixture is composed of gravel or cobble as its coarse grain and clay or sand as its filling.Whether natural or man-made,the mechanical properties of this material are widely different from homogeneous and continuous soil or rock.The engineering background of this paper is the high fill of Kunming new airport project in which a large number of soil-aggregate mixtures will be used as filling material.Through the numerical simulation of confined compression tests with 3D particle flow models,we compared the micromechanical fabrication and basic mechanical properties of the soil-aggregate mixture with different grain size distributions.Then we put forward a zone of the ratio of rock to soil which could be used in the project.The influence of different ratios of the stone in the mixture to their fabrication was also investigated.This simulation is a valuable attempt for application of particle flow method to practical engineering project.