不同干密度压实黄土垂直积水入渗特性

为探究受干密度变化影响下的压实黄土垂直积水入渗特性，以延安黄土为例，利用自主研发的一套一维土柱垂直入渗试验装置，设置三组不同干密度压实土柱进行常水头积水入渗试验。结果表明：入渗率和湿润锋前进速率与压实黄土干密度存在负相关性，导致相同积水入渗时段，干密度越大，累积入渗量越少，湿润锋前进距离越短；干密度变化对入渗率影响主要体现在积水入渗前期，随时间推移影响程度逐渐减小；积水入渗试验中，同一深度相邻传感器响应时间间隔与压实黄土干密度存在正相关性，且干密度越大，土体增湿过程越相对缓慢；试验土体增湿过程中，渗透系数逐渐增大，介于10-9～10-4cm/s之间，当体积含水率在20%～30%时，渗透系数受干密度变化影响不明显，当体积含水率大于30%，干密度越大渗透系数越小；压实黄土增湿稳定时，体积含水率小于饱和态，渗透系数近似等于饱和渗透值。

Study on the Infiltration Characteristics of Vertical Water in Different Dry Density Compacted Loess

In order to explore the vertical water infiltration characteristics of compacted loess affected by the change of dry density. Taking Yan''an loess as an example, a set of independently developed one-dimensional soil column vertical infiltration test equipment was used to set up three sets of compacted soil columns with different dry densities to carry out the constant head water infiltration test. The results show that there is a negative correlation between the infiltration rate and the advance rate of the wet front and the dry density of the compacted loess. During the same period of infiltration of stagnant water, the greater the dry density, the less the cumulative infiltration, and the shorter the distance of the wetting front. The influence of dry density change on the infiltration rate is mainly reflected in the early stage of infiltration of stagnant water, and the degree of influence gradually decreases with the passage of time. In the water infiltration test, there is a positive correlation between the response time interval of adjacent sensors at the same depth and the dry density of compacted loess, and the higher the dry density, the slower the soil humidification process. In addition, during the humidification process of compacted loess, the permeability coefficient gradually increases, ranging from 10-9 cm/s to 10-4 cm/s. When the volumetric water content is between 20% and 30%, the permeability coefficient is not significantly affected by the change of dry density. When the volumetric water content is greater than 30%, the larger the dry density, the smaller the permeability coefficient. When the compacted loess is humidified and stable, the volumetric water content is less than the saturated state, and the permeability coefficient is approximately equal to the saturated permeability value.