FIELD TECHNIQUES FOR MEASURING FIELD SATURATED AND UNSATURATED HYDRAULIC CONDUCTIVITY USING SOIL MOISTURE PROFILE

摘要

A new field experimental method of determining the hydraulic conductivity of unsaturated soils in the near surface of homogeneous sandy soils is proposed. Firstly a ponded single-ring infiltrometer technique, such as the Guelph Pressure Infiltrometer method was performed to determine the field-saturated hydraulic conductivity of soil. Secondly the instantaneous profile method with the unit hydraulic gradient assumption was applied to determine the unsaturated hydraulic conductivity of soil during drainage test. The vertical soil moisture profiles during the permeability tests were measured by a portable soil moisture device.The advantage of our proposed method is to measure the field-saturated and the unsaturated hydraulic conductivity of soil continuously by quite simple in-situ permeability tests with soil moisture profiles. The utility of our proposed method is demonstrated by using a numerical example of sandy soil and experimental data of fine dune sand.