中文摘要：

地下水（潜水）位上升,在黄土（非饱和土）中会产生一种特殊的渗流现象——向上渗流。为了探索黄土中的向上渗流规律,自主研制了非饱和土向上渗流试验仪,对4组原状非饱和离石黄土试样（高20 cm,直径8 cm）均分别进行定压力水头为1 cm、5 cm、10 cm条件下的向上渗流试验,观察水在土中向上渗流的过程、渗流锋面形态及变化,从而获取渗流锋面位移-时间关系（渗流速度）、渗流压力-渗流速度关系等渗流特征参数,并分析不同条件下的向上渗流规律,得出如下主要结论：（1）渗流锋面位移与时间关系曲线呈似抛物线状;（2）依据渗流速率变化,可将渗流过程大致分为快速上渗期、缓慢上渗期、趋稳上渗期3个时段,对比分析得到定水头压力、干密度及天然含水率等因素对渗流速率的影响;（3）试验发现虫孔发育且贯通性良好在水分入渗过程中起到一定的促进作用,会加快向上渗流的速率,通过对所得试验数据进行回归分析,得到渗流锋面位移H与时间T的拟合公式。

英文摘要：

A special kind of seepage phenomenon, the upward seepage, occurs in the loess （ unsaturated soil） if the groundwater （phreatic water） level rises. In order to study the upward seepage law of the intact unsaturated Lishi loess under different conditions, an upward permeameter is designed in the unsaturated soil, and four groups of specimens （the height is 20 cm and the diameter is 8 cm） are selected to implement the upward seepage test under the constant pressure heads of 1, 5 and 10 cm. The process of upward water seepage and the shape and change of the seepage front in the loess are observed. The relationship between seepage frontal displacement and time （seepage velocity） and the relationship between seepage pressure and seepage velocity are obtained. The results show that （ 1 ） the curve showing the relationship between the seepage frontal displacement and time is a parabola. （2） According to the change in the seepage rate, the seepage process consists of three stages, i. e. , the fast, slow and stable stages, and comparison and analysis reveal the effects of constant head pressure, dry density and natural moisture content on the seepage rate. （3） It is found that the wormhole development and good connectivity can accelerate the rate of upward seepage. Using the obtained experimental data to run a regression, the fitting formula between seepage frontal displacement and time is attained.