膨胀性土壤饱和水分运动参数计算模型

膨胀性土壤吸水膨胀变形，具有复杂的水文特性及力学性质，其分布范围广泛，对国民经济有着重大影响，开展膨胀性土壤水分运动研究具有重要的实际意义和理论意义。目前的土壤水分运动研究多针对非膨胀性土壤，相关研究成果不适用于描述膨胀性土壤水分运动过程。土壤膨胀变形主要是土壤膨胀力和自重应力综合作用的结果，土壤受力变形特征随土壤深度的变化而变化。为量化土壤膨胀变形对土壤水分运动参数的影响，采用土壤膨胀特征曲线和土壤应力——应变关系曲线，建立了包括饱和含水量、饱和导水系数、饱和比容积等在内的膨胀性土壤饱和水分运动参数计算模型。随后，以黄绵土和娄土为典型膨胀性土壤，基于室内试验开展了不同厚度土壤饱和水分运动参数的测定，验证所提出的参数计算模型的适用性和可靠性。结果表明：土壤饱和水分运动参数的计算值与实测值间的相对误差均小于10%，Nash效率系数均大于0.85，均方根误差均小于0.07，说明该模型可以较好地模拟计算膨胀性土壤饱和水分运动参数。研究成果既丰富了土壤水分运动理论研究，也为膨胀性土壤水分的利用和管理提供了参考。未来研究将深入探讨不同初始含水量、不同初始容重下，土壤自重应力和膨胀力对饱和水分运动的影响，以期进一步提高模型性能。

Swelling Soil Saturated Water Movement Parameters Calculating Models

The soil swelling deformation will happen when swelling soils absorb water. Swelling soils are widely distributed in the world, which have complex hydrological characteristics and mechanical properties, and have significant influence on the national economy. As the current research on soil water movement is mostly aimed at non-swelling soil, the related research results are not suitable for describing the process of swelling soil water movement. Consequently, it is of great practical and theoretical significance to carry out the study of swelling soil moisture movement. The soil swelling deformation is mainly the result of the combined effect of the soil swelling pressure and self-weigh stress, and the stress and deformation characteristics of swelling soils vary with the soil depth. To quantify the effect of the soil swelling deformation on water movement parameters, the calculating models of parameters including saturated water content, saturated water conductivity and saturated ratio of volume were established by using soil swelling characteristic curve and soil stress-strain relationship curve. Then, Loessial soil and Lou soil were selected as typical swelling soils, and their saturated water movement parameters in different soil thickness were measured based on the indoor experiment, and the applicability and reliability of the parameters were verified. The results show that the relative error are less than 10%, RSME are less than 0.07, and Nash efficiency coefficient are larger than 0.85 between the observed and predicted values of the three parameters, which indicates that the calculating models can be applied to simulate swelling soil saturated water movement parameters. The results enrich the theoretical research of soil water movement, and provide reference for swelling soil water utilization and management. In future, to improve the performance of the model, the effect of the soil swelling pressure and self-weigh stress on saturated water movement parameters under different initial water content and different initial bulk density needs to be explored.