单、双孔隙结构非饱和黏土孔隙分布变化规律试验研究

Experimental study on the variation pattern of pore size distributions for unsaturated clay with single or double pore structure

由于孔隙分布曲线的复杂性,在非饱和过程中黏土的孔隙结构变化规律尚不明晰,这导致基于孔隙分布模型计算土-水特征曲线存在较大的误差。针对这一问题,基于干缩试验与压汞试验,对单孔与双孔结构重塑黏土在脱湿过程中孔隙分布曲线的变化规律进行了定量分析。研究表明:在脱湿过程中孔隙分布曲线存在平移、缩放等变换。构建了t分布和双t分布函数,提取了孔隙分布曲线的自由度、峰值、峰值对应的孔隙直径作为特征参数来表征孔隙分布变化规律,发现了特征参数和土样孔隙比之间存在较好的线性关系。基于试验结果,建立了含水率-孔隙比-孔隙分布曲线关系,提出了一个考虑孔隙结构变化的重塑黏土土-水特征曲线计算框架。最后,与试验测得的土-水特征曲线进行比较,验证了所提出的计算方法的准确性。

Due to the complexity of the pore size distribution(PSD),the variation pattern of the pore structure for clay during the drying process is not clear,which leads to an inaccurate calculation of the soil-water characteristic curve(SWCC) based on the pore distribution model.To address this issue,a study was conducted to quantitatively analyze the PSD of remodeled clay with the single or double pore structure during the drying process based on the shrinkage test and mercury intrusion porosimetry test.The results revealed that there were translational and scaling transformations of the PSDs during the drying process.The t-distribution and double t-distribution functions were proposed to describe the PSDs of clay.The degrees of freedom,the peaks and the pore diameters corresponding to the PSD peaks were extracted as characteristic parameters to characterize the variation of PSDs.Good linear relationships between the characteristic parameters and the void ratio of remodeled clay were observed.Based on these findings,the relationship of water content-void ratio-pore size distribution was further established,and a framework for calculating the SWCC of remolded clay considering the variation of pore structure was proposed.Finally,the accuracy of the proposed calculation method was verified by comparing with the experimentally measured SWCC.