土–石混合体随机细观结构生成系统的研发及其细观结构力学数值试验研究

DEVELOPMENT OF RANDOM MESOSTRUCTURE GENERATING SYSTEM OF SOIL-ROCK MIXTURE AND STUDY OF ITS MESOSTRUCTURAL MECHANICS BASED ON NUMERICAL TEST

土–石混合体的细观结构特征在很大程度上影响了其在外力作用下的细观损伤演变机制及所表现的宏观力学行为。从土–石混合体的细观结构特征出发,开展一系列相关细观力学特征研究工作,将对于深化土–石混合体力学理论研究体系具有重要的意义。运用统计学、几何学、随机模拟等多学科交叉技术,开发基于任意凸多边形及椭圆形块石的土–石混合体细观结构随机生成系统——R-SRM2D。基于R-SRM2D,从土–石混合体的含石量、粒度组成、块体空间分布及土–石界面类型等特征的差异性出发,运用数值试验的方法研究土–石混合体细观结构的差异与其细观损伤机制及宏观力学行为的关系。在理论上取得一些有意义的研究成果:随着含石量的增加,土–石混合体弹性模量及单轴抗压强度呈上升趋势;在含石量一定的条件下,试样的宏观强度随着块石粒度维数的增加而略有降低;当块石长轴与主压力轴近于正交或平行时,其抗压强度最大;当块石长轴与主压力轴成(45°-?s/2)时,其抗压强度最小;土–石界面的胶结使得土–石混合体的宏观强度发生明显的改善,其单轴抗压强度增加约1倍。

The mesostructure characteristics significantly affect meso-failure evolution mechanism and the macromechanical characteristics of soil-rock mixture（S-RM） under external forces. It is very important for the improvement of theoretical system of S-RM mechanics to study the mesostructural mechanics of S-RM based on its mesostructural characteristics. Accordingly, the statistics, geometry, random simulation techniques, etc. are used, and the random mesostructure generation system of S-RM based on arbitrary polygonal and elliptic rock blocks（R-SRM^2D） has been developed. Based on R-SRM^2D, a series of random S-RM samples with different rock block contents, granularity compositions, rock block spatial distributions and soil-rock interfaces are generated, which is used to study the relationship between mesostructure difference and meso-failure mechanics or macromechanical characteristics of S-RM by numerical test. Meaningful results have been obtained theoretically. It is indicated that with the increment of rock block content, the elastic modulus and uniaxial compressive strength of S-RM increase; at a certain rock block content, the macro-strength of S-RM decreases with the increment of rock block fractal dimension; the compressive strength of S-RM reaches maximum value when the longer axis of rock blocks is perpendicular or parallel to the principal stress axis; when the angle between the longer axis of rock blocks and the principal stress axis is equal to （45°-φs/2）, the compressive strength of S-RM reaches minimum value; the cementation action of soil-rock interface makes the macro-strength of S-RM increases obviously, whose uniaxial compressive strength increases nearly twice.