原状黄土的孔径分布特征分析

Analysis on Pore-size Distribution Characteristics of Undisturbed Loess

基于土-水特征曲线,以陇东高原典型黄土为研究对象,对原状黄土的孔径分布进行理论计算,得到了原状黄土的比表面积和总孔隙体积值、基质吸力与孔隙半径、单位质量土体孔隙体积与平均孔径、单位质量土体的累积孔隙体积与平均孔径的关系。数据拟合的结果表明:基质吸力的对数与孔隙半径呈幂函数关系,当孔隙半径<50 000时,基质吸力随着孔隙半径的增大而迅速减小,而在孔隙半径>50 000以后,基质吸力随孔隙半径的增大变化量很小。单位质量土体的孔隙体积与平均孔径近似呈线性关系,而单位质量土体的累积孔隙体积与平均孔径呈指数关系。研究结果可为黄土的物理力学特性及水理特性研究提供理论基础。

Based on soil-water characteristic curve,this paper,taking the typical loess in Longdong plateau as the study object,made the theoretical calculation on the pore-size distribution of undisturbed loess,and concluded the relations between the specific surface area and total pore volume,the matric suction and pore radius,the pore volume per unit mass of soil and average pore size,the accumulated pore volume per unit mass of soil and average pore size,respectively. The result of data fitting shows that the logarithm of matric suction relates to pore radius in power function,thus the matric suction decreases rapidly with the pore radius when the pore size is less than 50 000,but has little change when the pore size is more than 50 000. The pore volume per unit mass of soil and average pore size present a linear relation approximately,while the accumulated pore volume per unit mass of soil and average pore size an exponential relation. The study result may provide theoretical basis for the research on physical and mechanical properties and hydraulic characteristics of loess.