三峡库区紫色土土-水特征曲线模型对比研究  

Comparative Study of Soil-Water Characteristic Curve Model of Purple Soil in the Three Gorges Reservoir Area

作　　者：杨寻 汪时机[1,2] 李贤 黎桉君[1] 夏浩城[1] 张继伟 YANG Xun;WANG Shiji;LI Xian;LI Anjun;XIA Haocheng;ZHANG Jiwei(College of Engineering and Technology,Southwest University,Chongqing 400715,China;Chongqing Engineering Research Center for Structure Full-Life-Cycle Health Detection and Disaster Prevention,Chongqing 408100,China)

机构地区：[1]西南大学工程技术学院,重庆400715 [2]重庆市建筑物全生命周期健康检测与灾害防治工程研究中心,重庆408100

出　　处：《西南大学学报（自然科学版）》2023年第8期201-210,共10页Journal of Southwest University(Natural Science Edition)

基　　金：国家自然科学基金项目(11972311);西南大学创新研究2035先导计划项目(SWU-XDPY22003).

摘　　要：土水特征曲线(SWCC)本构模型是非饱和土力学研究中重要的本构关系,它是反映非饱和土持水特性的重要表征曲线.SWCC的影响因素很多,外部因素如应力状态、气候变化等,内部因素如干密度、孔隙连通状态、矿物成分等.本文基于滤纸法试验,测定三峡库区重庆段非饱和紫色土土水特征曲线,考虑其拟合参数对于分析非饱和土的持水特性具有重要意义,采用Gardner、van Genuchten、Fredlund-Xing、双应力变量广义土水特征曲线模型(W-G)等4种模型对试验结果进行拟合,通过整体拟合与分点拟合对比验证W-G模型的拟合效果;进而依据W-G模型探讨初始干密度对非饱和紫色土土水特征曲线的影响规律.结果表明:①从整体拟合来看van Genuchten和W-G模型拟合效果最好;从分点拟合来看,与van Genuchten模型相比,W-G模型的拟合精度更好且更稳定,对试验数据量的依赖程度较低.②初始干密度对非饱和紫色土土水特征曲线有较显著的影响;干密度大的土样具有较低的初始饱和含水率、较高的进气值和良好的持水性能,SWCC形态平缓;与土体进气值相关的参数α随干密度增大呈幂函数减小,土壤的实际残余含水率随干密度增大呈线性增长.W-G模型可以很好地描述和预测非饱和紫色土的持水特性,特别适用于试验数据点不多的情况.The constitutive model of the soil-water characteristic curve is an important constitutive relation in the study of unsaturated soil mechanics.It is an important characterization curve reflecting the water-holding characteristics of unsaturated soil.There are many factors affecting the soil-water characteristic curve,including external factors such as stress state,climate change,and internal factors such as dry density,pore connectivity state,mineral composition.In this paper,based on the filter paper method test,the soil-water characteristic curve of the unsaturated purple soil in the Chongqing section of the Three Gorges Reservoir was determined.Since its fitting parameters are of great significance for analyzing the water-holding characteristics of unsaturated soils,four models,Gardner,van Genuchten,Fredlund-Xing,and two-stress variable generalized soil-water characteristic curve model(W-G),were used to fit the test results.Then,the fitting effect of the W-G model was verified by comparing the overall fitting and the point fitting.Furthermore,the regularity of the influence of initial dry density on the soil-water characteristic curve of unsaturated purple soil was discussed based on the W-G model.The results show that:①From the overall fitting point of view,the van Genuchten and W-G models have the best fitting effect.From the point of point fitting,compared with the van Genuchten model,the fitting accuracy of the W-G model is better and more stable.Data volume dependency is lower.And W-G is less dependent on the amount of experimental data.②The initial dry density has a significant effect on the soil-water characteristic curve of unsaturated purple soil.Soil samples with high dry density have lower initial saturated water content,higher air intake value and good water holding capacity.Its corresponding SWCC is relatively flat.The parameterαrelated to the air intake value of the soil decreases as a power function with the increase of the dry density,and the actual residual water content of the soil incre

关 键 词：非饱和紫色土 土水特征曲线 初始干密度 持水特性 滤纸法 

分 类 号：TU43[建筑科学—岩土工程]