Lee Bong-Joo
Korea Institute of Geoscience and Mineral Resources, Daejeon, 34132, South Korea.
Sci Rep. 2024 Aug 2;14(1):17928. doi: 10.1038/s41598-024-68887-6.
This study presents a novel permeameter design for field falling-head tests to determine vertical hydraulic conductivity (K) using Darcy's equation. The design features an open-ended standpipe with two ports for simultaneous measurement of hydraulic heads at both ends of the sediment column, enabling direct estimation of flow rate (q) and hydraulic gradient (i). Flow rate is calculated by differentiating the best-fit curve for water level change above the sediment, and the hydraulic gradient is derived from the head difference between the ports. Laboratory and field tests consistently demonstrated a strong linear relationship between q and i (R > 0.999), validating the applicability of Darcy's equation for this new permeameter design. The K values obtained using the proposed method matched those obtained using the Hvorslev equation method. Furthermore, the design allows for continuous measurement of heads after the falling-head permeameter test, facilitating the collection of time series data for the hydraulic gradient. When combined with a pre-determined K value, this enables calculation of time series for the seepage rate across the surface water/sediment interface. To demonstrate this capability, preliminary tests were conducted using commercially-available pressure transducers to monitor heads and obtain seepage time series. The results of these tests are also presented.
本研究提出了一种用于现场常水头试验的新型渗透仪设计，以利用达西方程确定垂直水力传导率（K）。该设计的特点是有一个开口立管，带有两个端口，用于同时测量沉积柱两端的水头，从而能够直接估算流量（q）和水力梯度（i）。流量通过对沉积物上方水位变化的最佳拟合曲线求导来计算，水力梯度则由端口之间的水头差得出。实验室和现场测试一致表明q和i之间存在很强的线性关系（R＞0.999），验证了达西方程对这种新型渗透仪设计的适用性。使用所提出方法获得的K值与使用Hvorslev方程方法获得的K值相匹配。此外，该设计允许在常水头渗透仪试验后连续测量水头，便于收集水力梯度的时间序列数据。当与预先确定的K值相结合时，这能够计算地表水/沉积物界面处渗流率的时间序列。为了展示这种能力，使用市售压力传感器进行了初步测试，以监测水头并获得渗流时间序列。还给出了这些测试的结果。
