全吸力范围内渗透系数快速测定方法研究

非饱和土渗透系数函数跨越多个数量级，传统的测量方法动辄耗时数月，且难以实现全吸力范围内渗透系数的测量。为了实现全吸力范围内渗透系数的快速测量，将湿润锋前进法与瞬时剖面法相结合（简称联合测定方法），利用自行研制的土柱入渗装置，开展了不同干密度条件下青海粉质黏土全吸力范围内渗透系数测量试验。试验结果表明：在联合测定方法中，湿润锋前进法适用于高吸力段（基质吸力ψ > 25 kPa）渗透系数的测量，瞬时剖面法则适用于低吸力段（基质吸力ψ ≤25 kPa）渗透系数的测量，且两种方法在吸力重叠范围内渗透系数测量结果基本一致。联合测定方法可将全吸力范围内渗透系数的测量时长压缩至一周左右，且精度良好。此外，还对两种试验方法的误差来源进行了分析与讨论。研究结果表明：联合测定方法能够实现全吸力范围内渗透系数的快速测量，有望使得非饱和土渗透系数的测量成为土力学的常规试验。

A rapid determination method of hydraulic conductivity in full suction range

The hydraulic conductivity function of unsaturated soil spans several orders of magnitude. Traditional measurement methods often take several months, and it is difficult to measure the hydraulic conductivity in the full suction range. In order to realize the rapid measurement of hydraulic conductivity in the full suction range, the wetting front advancing method is combined with the instantaneous profile method (here referred to as the combined determination method) in this study. A self-developed soil column infiltration device was used to measure the hydraulic conductivity of Qinghai silty clay in the full suction range under different dry densities. The test results show that in the combined determination method, the wetting front advancing method is suitable for the measurement of hydraulic conductivity in the high suction range (ψ > 25 kPa), while the instantaneous profile method is suitable for measuring the hydraulic conductivity in the low suction range (ψ ≤25 kPa). The hydraulic conductivity determined by the two methods in the overlapped suction range is basically consistent. The combined determination method can reduce the measurement time of hydraulic conductivity in the full suction range by about one week with good accuracy. In addition, the error sources of the two measurement methods are also analyzed and discussed in this work. The results show that the combined determination method can realize the rapid measurement of hydraulic conductivity in the full suction range, which is expected to make the measurement of the hydraulic conductivity of unsaturated soil become a routine test in soil mechanics.