基于季节性河床砂样的垂向非饱和入渗试验研究

Experimental Study on Vertical Unsaturated Infiltration in Soil Column Based on the Seasonal River Sand

摘要: 基于季节性河床砂样，开展了垂向非饱和入渗室内试验，研究了影响垂向入渗的主要因素。结果表明，非饱和入渗随时间的变化可分为3个阶段，第1个阶段为入渗率迅速下降期，第2个阶段为入渗率缓慢下降期，第3个阶段为入渗率渐近稳定期；砂样的初始含水率、砂样质地对入渗特性产生明显影响。垂向入渗速度随着初始含水率的增大而减小，随着砂样干容重的增大而减小；当初始含水率分别为1.02%和5.11%时，细砂的稳定入渗率约为0.027 mL/(s•cm²)和0.021 mL/(s•cm²)；当初始含水率分别为1.38%和3.51%时，中砂的稳定入渗率约为0.028 mL/(s•cm²)和0.026 mL/(s•cm²)；当初始含水率分别为1.83%和5.92%时，粗砂的稳定入渗率约为0.030 mL/(s•cm²)和0.029 mL/(s•cm²)。粗砂的稳定入渗率大于细砂。试验结果对于深入研究季节性河道渗漏规律提供了科学依据。

Abstract: Based on the seasonal river sand, laboratory test was carried out by vertical unsaturated infiltration and it studied the main factors influencing the vertical infiltration. The results show that the unsaturated in-filtration can be divided into three stages changing with time. In the first stage, the infiltration rate drops rapidly. In the second stage, the infiltration rate declines slowly. And in the third stage, the infiltration rate is asymptotically stable. The initial moisture content of sample and sample texture obviously influ-ence on infiltration characteristics. Vertical infiltration velocity decreases with the increase of initial moisture content, as the sample decreases with the increase of dry density. When the initial moisture content was 1.02% and 5.11%, the stability infiltration rate of fine sand was about 0.027 mL/(s•cm²) and 0.021 mL/(s•cm²). When the initial water content rate was 1.38% and 3.51%, the stability infiltration rate of medium sand was about 0.028 mL/(s•cm²) and 0.026 mL/(s•cm²). The initial moisture content was about 1.83% and 5.92% when the stability infiltration rate of coarse sand was about 0.030 mL/ (s•cm²) and 0.029mL/(s•cm²). The stability infiltration rate of the coarse sand is greater than the fine sand. The test results provide a scientific basis for the further study of seasonal river seepage law.