Butler James J, Dietrich Peter, Wittig Volker, Christy Tom
Kansas Geological Survey, The University of Kansas, 1930 Constant Avenue, Lawrence, KS 66047, USA.
Ground Water. 2007 Jul-Aug;45(4):409-19. doi: 10.1111/j.1745-6584.2007.00300.x.
The direct-push permeameter (DPP) is a promising approach for obtaining high-resolution information about vertical variations in hydraulic conductivity (K) in shallow unconsolidated settings. This small-diameter tool, which consists of a short screened section with a pair of transducers inset in the tool near the screen, is pushed into the subsurface to a depth at which a K estimate is desired. A short hydraulic test is then performed by injecting water through the screen at a constant rate (less than 4 L/min) while pressure changes are monitored at the transducer locations. Hydraulic conductivity is calculated using the injection rate and the pressure changes in simple expressions based on Darcy's Law. In units of moderate or higher hydraulic conductivity (more than 1 m/d), testing at a single level can be completed within 10 to 15 min. Two major advantages of the method are its speed and the insensitivity of the K estimates to the zone of compaction created by tool advancement. The potential of the approach has been assessed at two extensively studied sites in the United States and Germany over a K range commonly faced in practical field investigations (0.02 to 500 m/d). The results of this assessment demonstrate that the DPP can provide high-resolution K estimates that are in good agreement with estimates obtained through other means.
直推式渗透仪（DPP）是一种很有前景的方法，可用于获取浅层松散地层中水力传导率（K）垂直变化的高分辨率信息。这种小直径工具由一个短的滤网段组成，在滤网附近的工具中嵌入一对传感器，将其推入地下至所需估算K值的深度。然后进行一个简短的水力试验，以恒定速率（小于4升/分钟）通过滤网注入水，同时在传感器位置监测压力变化。根据达西定律，利用注入速率和压力变化，通过简单公式计算水力传导率。对于中等或更高水力传导率（大于1米/天）的情况，在单个深度进行测试可在10至15分钟内完成。该方法的两个主要优点是速度快，且K值估算对工具推进所产生的压实区不敏感。在美国和德国的两个经过广泛研究的场地，针对实际野外调查中常见的K值范围（0.02至500米/天）评估了该方法的潜力。评估结果表明，直推式渗透仪能够提供与通过其他方法获得的估算值高度一致的高分辨率K值估算。
