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土的宏观力学行为究其原因是微观结构的外在反映。为了研究粉砂土微观结构在冻融循环作用下的变化对宏观力学特性的影响规律,通过对不同含水量下粉砂土的平均粒径、粒度分维、颗粒定向概率熵、颗粒起伏分维、平均孔径、平均丰度、孔径分维、平均圆形度等8个微观参数的观测,基于灰色关联理论,分析了微观结构特性与粉砂土的内摩擦角、黏聚力以及粉砂土路基抗剪强度等宏观力学行为的关联性。研究结果表明:平均丰度、平均孔径与内摩擦角的关联性较大,关联度大于0.64;平均粒径、粒度分维、颗粒定向概率熵与黏聚力的关联性较大,其关联度大于0.64;平均粒径、定向概率熵、粒度分维、颗粒起伏分维与粉砂土路基抗剪强度关联性较大,关联度大于0.64,其中平均粒径、定向概率熵与粉砂土路基抗剪强度的关联度大于0.8,说明二者与粉砂土路基抗剪强度密切相关。
The reason for the macroscopic mechanical behavior of soil is the external reflection of the microstructure. In order to study the influence of the change of microstructure on the macroscopic mechanical properties of the silty sand under the action of freeze-thaw cycles, the average particle size, the fractal dimension, the directional entropy of grain orientation, the fractal dimension , Average pore size, average abundance, pore size fractal dimension, average circularity and so on. Based on the gray relational theory, the relationship between microstructure characteristics and internal friction angle, cohesion and silt sand Shear strength of subgrade and other macroscopic mechanical behaviors. The results show that the average abundance, mean pore size and internal friction angle are relatively large, the correlation is greater than 0.64. The average particle size, particle size fractal dimension, particle orientation probability entropy and cohesion are more related, Greater than 0.64. The average particle size, directional probability entropy, particle size fractal dimension and particle fluctuation fractal dimension are more related to the shear strength of silty sand subgrade, and the correlation degree is greater than 0.64. The mean particle size, directional probability entropy and silty sand subgrade The correlation of shear strength is greater than 0.8, which shows that the two are closely related to the shear strength of silty sand subgrade.