利用瞬态剖面法测定非饱和黄土的渗透性曲线

瞬态剖面法是量测非饱和土渗透系数的直接方法之一。本文以室内模型试验为基础，利用瞬态剖面法测量重塑黄土试样的非饱和渗透系数。试验以陕西泾阳泾河南岸的黄土塬南缘马兰黄土为对象，将重塑干黄土样筛入一圆形玻璃筒内，上部补给一定量的水，然后量测不同时刻土柱内不同深度的质量含水量，并换算为体积含水量；同时采用张力计法测定模型桶土样的土-水特征曲线，即不同含水量土样的基质吸力。计算得到不同时刻模型桶内土样的水头剖面，由此确定渗流速度和水力梯度，并得出不同体积含水量土样的渗透系数。对瞬态剖面法得到重塑黄土样的非饱和渗透系数进行回归分析，获得渗透系数与含水量，渗透系数与基质吸力的指数函数关系。

Use of instantaneous profile method to determine permeability function of unsaturated loess

The instantaneous profile method is one of the direct methods to determine the unsaturated permeability function .In this paper, we use the method of the instantaneous profile to determine the unsaturated permeability function of unsaturated loess ,based on the laboratory model test. The experiments is on typical Malan loess in southern bank of Jinghe River. We load the disturbed loess into a glass cylinder, then supply a certain amount of water on the upper. The profiles of water content in a soil sample are obtained in different time by measuring water content in different depth long water flow direction. Determining the soil-water characteristic curve of laboratory model test sample by tensionmeter, we can get the corresponding matric suction of different water content. And the profiles of hydraulic head are obtained. So we determine the water flow rate and the hydraulic head gradient, the unsaturated coefficients of permeability is computed by dividing the flow rate by the average hydraulic head gradient. Among them, the soil sample volume moisture content measured with soil oven drying method, and the soil water characteristic curve determined by TEN 15 tensionmeter. Finally, we get the permeability function by fitting the date we calculated.