关键词: 压力板仪, 土-水特征曲线, 取样称量法, 溢出水称量法, 溢出水校正称量法

Abstract:

Usually, two methods are adopted in using the pressure plate extractor, namely, including the weighing soil method(WSM), which measures the water content by weighing the soil sample when equilibrium is reached; and the weighing outflow method(WOM), which measures the water content by weighing the outflow from the soil sample after equilibrium is attained. In the measurement, however, there are some factors that can adversely influence testing results. For example, with the WSM, part of soil mass may lose, and in using the WOM, the outflow could be overestimated because the air-bubble accumulation and the air-water interface. All these factors may result in error. To resolve the problem, an adjusted method of weighing ouflow is introduced. By comparing the weighing soil method and the weighing outflow method to the adjusted method of weighing outflow, it is shown that at the same matric suction, the saturations determined with the weighing soil method and the weighing outflow method are less than that determined with the adjusted method of weighing outflow. The reasons for this are sought; and the applicabilities of these three methods are discussed.

Key words: pressure plate extractor, soil water characteristic curve, weighing soil method, weighing outflow method, adjusted weighing outflow method