摘要
在自然环境和工程实践中,广泛存在多层非饱和土中水的渗流现象。为准确描述时变降雨场景下双层非饱和土中水分一维瞬态渗流行为,基于指数型的土-水特征曲线及渗透系数函数,首先,利用变量代换、分离变量和Fourier级数变换法推导得到了相应解析解,该解析解还考虑了任意初始含水率分布和两类底部边界;在此基础上,通过与现有两个解析解和相应数值解比较,充分验证了所提解析解正确性;最后,以简化双层土质盖层为例,分析了水分在双层非饱和土中一维瞬态渗流规律。结果表明:在总降雨量相同情况下,“前峰型”降雨模式下盖层中的储水量较小,累计渗漏量CQb较大,“后峰型”降雨模式则与之相反;相比于饱和渗透系数较小的土质盖层位于双层盖层上方的情况,其位于下方时对应的储水量较大,CQb值较小;当初始总储水量相同时,底部体积含水率越大,降雨一段时间后盖层中的储水量越小,CQb值越大;盖层的初始有效饱和度Sini越大,降雨过程中CQb值也越大,且在同一时刻,CQb值随Sini增大呈线性增大趋势。
The seepage phenomenon of water in multi-layered unsaturated soils is ubiquitous in natural environments and engineering practices.To accurately describe the one-dimensional transient seepage behavior of water in the two-layered unsaturated soil under a time-varying rainfall scenario,based on the exponential soil-water characteristic curve and permeability coefficient function,the corresponding analytical solutions are derived for the first time via the approach of variable substitution,separation variable,and Fourier series transformation.The solutions also account for the arbitrary initial water content distribution and two types of bottom boundary.On this basis,the correctness of the proposed analytical solutions is validated by comparing them with existing two analytical solutions and corresponding numerical solutions.Finally,taking the simplified two-layered soil cover as an example,the one-dimensional transient seepage laws of water in the two-layered unsaturated soil are analyzed.The results indicate that,for the same total rainfall,water storage in the cover is smaller and cumulative leakage CQb is larger under the“previous-peak”rainfall pattern,while the opposite occur under the“post-peak”pattern.Compared to the case where the soil cover with a smaller saturated permeability coefficient is located above the two-layered cover,the corresponding water storage is larger and the value CQb is smaller when it is located below.When the initial total water storage is the same,the larger volumetric water content at the bottom zone,the smaller water storage in the cover after a period of rainfall,and the larger value of CQb.A larger initial effective saturation of the cover Sini leads to a larger value of CQb during the rainfall,and at the same time,the value of CQb increases linearly with an increasing Sini.
作者
江文豪
王浩
廖光志
陈滨华
JIANG Wen-hao;WANG hao;LIAO Guang-zhi;CHEN Bin-hua(Zijin School of Geology and Mining,Fuzhou University,Fuzhou,Fujian 350108,China;Fujian Geotechnical Engineering Investigation Institute Co.,Ltd.,Fuzhou,Fujian 350108,China)
出处
《岩土力学》
北大核心
2025年第9期2721-2737,共17页
Rock and Soil Mechanics
基金
福州大学科研启动基金项目(No.511503)
国家自然科学基金面上项目(No.42477165)。
关键词
双层非饱和土
瞬态渗流
时变降雨
解析解
初始含水率分布
底部边界类型
two-layered unsaturated soil
transient seepage
time-varying rainfall
analytical solution
initial water content distribution
bottom boundary type
作者简介
第一作者:江文豪,男,1996年生,博士,副教授,主要从事边坡工程、环境岩土工程方面的研究。E-mail:Geo_Jiang2020@163.com;通讯作者:王浩,男,1978年生,博士,教授,主要从事地质灾害防治、环境岩土工程等方面的研究。E-mail:h_wang@126.com。
