Device and method for determining permeation coefficient of unsaturated soil

Abstract

The invention provides a device for determining the permeation coefficient of unsaturated soil. The device is characterized in that the upper end of a stainless steel tank is provided with an upper reverse filter apparatus, and the lower end of the stainless steel tank is provided with a lower reverse filter apparatus; the longer surface of the stainless steel tank is provided with an open end surface, and the open end surface is provided with toughened glass for closing the open end surface; and a plurality of soil water sensors and soil tension meters are respectively arranged on at least one end surface of the stainless steel tank from top to bottom. Compared with present devices and the prior art, the device and a method for determining the permeation coefficient of the unsaturated soil provided by the invention have the following beneficial effects: the permeation coefficient of the unsaturated soil can be directly obtained through simple one-dimensional infiltration tests and through utilizing an iterative method, the device is simple to manufacture, the measure precision is high, the unsaturated permeation coefficient of a sample can be measured, and the soil-water characteristic curve of the sample can also be measured.

Description

technical field [0001] The invention relates to the field of measuring unsaturated soil in civil engineering, in particular to a device and a method for measuring the permeability coefficient of unsaturated soil. Background technique [0002] The permeability coefficient of unsaturated soil is an important parameter to analyze the impact of rainfall on soil slope stability, solid waste landfill, migration of underground sewage and earth filling engineering problems. However, due to the existence of matric suction in unsaturated soil, the permeability coefficient cannot be determined by the conventional saturated permeability test method, which makes it difficult to determine the permeability coefficient of unsaturated soil. The hydraulic conductivity of unsaturated soil can be determined by direct or indirect methods. Direct measurement can be carried out in the laboratory or on site, but the measurement process takes a long time and requires high precision of the instrumen...

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Problems solved by technology

Direct measurement can be carried out in the laboratory or on site, but the measurement process takes a long time and requires high precision of the instrument. It is quite difficult to directly measure with existing testing methods; the indirect method requires the use of soil Volume-mass properties, soil-water characteristic curves, and saturated permeability coefficient of soil, and then predict the unsaturated soil permeability coefficient through empirical models. Based on this, many scholars have proposed various forms of permeability coefficient models, but different empirical models predict the obtained Under the same conditions, the soil permeability coefficients vary greatly, and there is no unified unsaturated permeability coefficient function

Therefore, no matter the direct or indirect method, there is no simple and feasible method to obtain the hydraulic conductivity of unsaturated soil

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