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土体是一种复杂的颗粒体系,其强度与变形具有显著的颗粒尺度效应。为考虑土体不同尺度土颗粒对其宏观力学特性的影响,根据土颗粒间相互作用产生的黏聚和摩擦物理效应而非纯粹几何尺寸,划分土颗粒尺度层次以构造反映土体内部材料信息和颗粒特征信息的土体胞元。基于土体不同尺度结构层次上力学响应的特征,引入微重比的概念,建立具有多尺度分层次理论框架的胞元土体理论,解释土体力学特性颗粒尺度效应的物理机制,把微细观土力学理论从定性分析推进到定量计算的水平。设计一系列饱和重塑土的三轴不固结不排水剪切试验对土体的颗粒尺度效应进行测试,并定量计算胞元土体理论的应变梯度和內禀尺度等微细观计算参数。试验和理论计算结果均表明,土体强度和变形的颗粒尺度效应随加强颗粒的体分比增加以及粒径减小而增强,反映出土体强度和变形显著的颗粒尺度效应;土体强度和变形尺度效应的理论预测与试验结果具有较好的一致性。
Soil is a complex particle system with significant grain-scale effects on its strength and deformation. In order to consider the influence of soil particles with different scales on the macroscopic mechanical properties of soil, according to the cohesion and friction physical effects caused by the interaction between soil particles rather than the pure geometric dimensions, the soil particle scale level is divided to construct the information reflecting the internal material and Soil characteristic cell information of soil cells. Based on the characteristics of mechanical response at different scales of soil structure, the concept of micro-weight ratio is introduced, and the theory of cell soil with multi-scale and hierarchical theory is established. The physical mechanism of particle-scale effect of soil mechanics is explained. Soil mechanics theory advances from qualitative analysis to the level of quantitative calculation. A series of three-axis unconsolidated undrained shear tests of saturated remolded soil were designed to test the effect of particle size on the soil mass. The parameters of the micro-scale such as strain gradient and intrinsic scale were calculated quantitatively. The results of experiments and theoretical calculations show that the grain-scale effect of soil strength and deformation increases with the increase of volume fraction and particle size of reinforced soil, which reflects the significant effect of soil particle size and grain size. The soil strength and deformation The theoretical prediction of scale effect has good consistency with the experimental results.