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非饱和土的本构关系研究需获得任意压缩变形条件下的土-水特征曲线,但试验测量往往只能给出特定状态下的土-水特征曲线。压缩变形改变了土体孔隙分布特性,从而影响其土-水特征曲线。采用压汞技术、核磁共振技术、扫描电镜研究压缩变形条件下土体孔隙孔径分布的变化规律,基于实测及已有试验数据研究土-水特征曲线变化规律,通过孔径分布变化规律阐释压缩变形影响土-水特征曲线的机制。研究结果表明:在不同的压缩变形条件下,土体(单位颗粒质量)的累计孔隙体积分布整体上呈现“扫帚型”分布,质量含水率表示的土-水特征曲线也呈现相似的分布,二者变化规律较为一致,从而揭示了土-水特征曲线随压缩变形变化的内在机理。在此基础上,建议了一种压缩变形影响下的土-水特征曲线简化表征方法,其描述的土-水特征曲线与试验结果吻合较好。
Soil-water characteristic curves under any compressive deformation are needed to study the constitutive relationship of unsaturated soils. However, soil-water characteristic curves under certain conditions are often given by experimental measurements. Compression deformation changes the soil pore distribution characteristics, thus affecting the soil-water characteristic curve. The variation of soil pore pore size distribution under compressive deformation was studied by mercury intrusion technique, nuclear magnetic resonance (NMR) and scanning electron microscope (SEM). The variation law of soil-water characteristic curve was studied based on measured data and existing experimental data. The influence of compressive deformation Mechanism of soil-water characteristic curve. The results show that under different compressive deformation conditions, the cumulative pore volume distribution of soil (unit mass) presents a “broom-like” distribution as a whole, and the soil-water characteristic curve of mass moisture content shows a similar distribution , Both of which are consistent with each other, revealing the intrinsic mechanism of the soil-water characteristic curve with compressive deformation. On this basis, a simplified method of soil-water characteristic curve under the influence of compressive deformation is proposed, and the soil-water characteristic curve described is in good agreement with the experimental results.