干湿循环作用下原状黄土渗透性及其对土-水特征曲线的影响
Permeability and Soil-Water Characteristic Curve of Undisturbed Loess under Wetting-drying Cycles
常洲 1晏长根 1安宁 2兰恒星 3石玉玲 4包含 1许江波1
作者信息
- 1. 长安大学公路学院,西安 710064
- 2. 中建五局投资管理公司,长沙 410116
- 3. 长安大学地质工程与测绘学院,西安 710054;中国科学院地理科学与资源研究所,北京 100101
- 4. 长安大学地质工程与测绘学院,西安 710054
- 折叠
摘要
为评估干湿循环作用对原状黄土水力特性的劣化效应,对甘肃Q3黄土进行了 4组不同干湿循环路径下的饱和渗透试验与土-水特征测试,分析土体饱和渗透系数和土-水特征曲线随干湿循环次数、循环幅度和下限含水率的变化规律.结果表明:原状黄土饱和渗透系数劣化度与干湿循环次数间关系可采用双曲线函数进行描述,6次循环后劣化度变化趋于稳定;土体饱和渗透系数劣化度随循环幅度增大而线性增大,随下限含水率增大而线性减小.V-G模型对干湿循环下黄土的土-水特征曲线拟合效果良好,模型参数θs、α、n变化幅度较小,而参数θr随循环次数增加呈指数下降趋势.依据试验结果建立了考虑干湿循环3参数的饱和渗透系数劣化模型与土-水特征曲线模型,并对土体非饱和渗透系数进行了预测分析.
Abstract
To assess the impact of wetting-drying cycles on the hydraulic properties of undisturbed loess,we per-formed saturated permeability tests and soil-water characteristic tests on Q3 loess from Gansu Province under four different wetting-drying cycle paths.The aim is to examine the changes in permeability and soil-water characteristic curves(SWCC)with the number of cycles,cycle amplitude,and lower bound water content.Results revealed that the deterioration of saturated permeability coefficients can be modeled using a hyperbolic function with respect to wetting-drying cycles.After six cycles,the deterioration tends to stabilize.As cycle amplitude increases,the deteri-oration of saturated permeability coefficients exhibits a linear increase,while a linear decrease with the rise in lower bound water content.The SWCC of loess can be represented by the V-G model;parameters θs,α,and n remain relatively unaffected,whereas the parameterθrdeclines exponentially with an increase in the number of cycles.De-terioration models for saturated permeability coefficients and SWCC models considering the above three parameters of wetting-drying cycles are established,enabling the prediction of unsaturated permeability coefficients of loess.
关键词
原状黄土/干湿循环/渗透系数/土-水特征曲线/劣化模型Key words
undisturbed loess/wetting-drying cycles/permeability coefficient/soil-water characteristic curve/deterioration model引用本文复制引用
基金项目
国家自然科学基金项目(42077265)
国家自然科学基金项目(42041006)
出版年
2024
国家科技期刊平台
NSTL
维普
万方数据