摘要
对浸润锋前进法、Boltzmann变换法和瞬态剖面法3种直接方法在确定增湿情况下重塑黄土非饱和渗透系数的适宜性进行了研究,并对其进行了改进。首先应用重塑黄土进行了一维水平入渗试验,对前2种方法进行了改进,检验了改进后的效果,比较了这2种改进方法、瞬态剖面法和间接法所得非饱和渗透系数的差异,然后应用Hydrus软件对一维入渗试验进行了数值模拟,获得了采用不同方法所得非饱和渗透参数时预测浸润锋迁移距离和时间关系的准确性,分析了前2种方法所采用假定的合理性并对瞬态剖面法测点布置进行了改进和效果检验。室内试验结果表明浸润锋前进法采用改进的水力梯度计算公式后,不同吸力下渗透系数波动的现象减少;Boltzmann变换法采用新的变量λ*后,各测点λ*-θ关系的统一性增加;由于测点间距较大,瞬态剖面法偏离其他方法所得渗透系数很大。数值模拟结果表明采用2种改进方法所得的非饱和渗透参数均能较好地预测浸润锋迁移距离和时间的关系;浸润锋前进法采用的水分剖面平行移动假定以及Boltzmann变换方法采用的Boltzmann变量与体积含水率关系唯一假定,均需要在入渗一定距离后才能得到基本满足;采用改进后的测点布置位置和间距后,瞬态剖面法所得不同吸力下的非饱和渗透系数与前2种改进方法所得的差距减少,但仍不如前2种改进方法更接近于输入值。
The suitability of three direct methods i.e. wetting front advancing method, Boltzmann transformed method and instantaneous profile method for determining the permeability coefficients of unsaturatedremolded loess under wetting condition were studied and the improvement of the three methods were made.Firstly,horizontal infiltration was carried out on the remolded loess. The first two method were improvedand the effectiveness was checked. The unsaturated permeability obtained by the two improved method,in-stantaneous profile method and two other indirect methods were compared. Then software Hydrus was usedto simulate the infiltration test by adopting the permeability parameters determined by the different methodsand the relationship of wetting front and time were compared with the measured value,and the hypothesisin wetting front advancing method and Boltzmann transformed method were analyzed. In addition,the im-provement of instantaneous profile method on the layout of measurement points and the effectiveness were al-so studied. The laboratory test results indicate that the permeability coefficient obtained by wetting front ad-vancing method adopting the new formula for hydraulic gradient is more stable. The relation between thenew Boltzmann transformed parameter λ＊and volumetric water content is more unified. The unsaturated per-meability coefficients obtained by instantaneous profile method deviates from that obtained by other methodsdue to large space between measure points. The numerical simulation results indicate that the hypothesis inwetting front advancing method,that is,the moisture profile move forward in parallel,and the hypothesisin Boltzmann method,that is,the relation between the Boltzmann transformed parameter and volumetric wa-ter content is unified,are reasonable only after the water infiltrating a certain distance. After adopting theimproved placement location and space of measurement points,the unsaturated permeability coefficient un-der different suction determined by the instantaneous profile method is more near to that obtained by thefirst two improved methods. However,these values determined by the first two improved methods are more close to the input values.
作者
胡海军
李常花
崔玉军
邵宗暄
艾一丹
HU Haijun;LI Changhua;CUI Yujun;SHAO Zongxuan;AI Yidan(College of Water Resources and Architectural Engineering,Northwest A＆F University,Yangling 712100,China;Department of Geotechnical Engineering,Tongfi University,Shanghai 200092,China;Ecole des Ponts Paris Tech,Laboratoire Navier/CERMES,Champs-sur-Marne 77455,France)
出处
《水利学报》
EI
CSCD
北大核心
2018年第10期1216-1226,共11页
Journal of Hydraulic Engineering
基金
国家自然科学基金青年科学基金项目(51409220)
西北农林科技大学基本科研业务费专项资金项目(2014YB049)
关键词
非饱和渗透系数
黄土
瞬态剖面法
浸润锋前进法
Boltzmann变量
unsaturated permeability coefficient
loess
instantaneous profile method
wetting front advancing method
Boltzmann transformed parameter
作者简介
胡海军（1982-），男，河南遂平人，讲师，博士，主要从事黄土力学与工程及颗粒介质宏微观力学特性研究。E—mail：hu．hai—jun@163．com
