Method used for measuring vertical saturation permeability coefficient of soil

Abstract

The invention relates to a method used for measuring the vertical saturation permeability coefficient of soil, belonging to the hydrologic survey field. In the method, the devices such as a single ring, a self recording level meter and a soil moisture content tester are adopted for measurement; then, according to the observed water-level fluctuation process of the single ring, by adopting the soil water motion computing method of Philip and Nestingen, a computational formula of the water-depth variation for describing the single-ring falling head permeability test is elicited, and the vertical saturation permeability coefficient of the soil can be calculated by adopting the principle of least square. The method can be used for measuring the vertical saturation permeability coefficient of the soil outdoors quickly and accurately. The instruments need little water, the devices are simple, the outdoor carrying is convenient, and the radius of the permeated single ring is not limited when in measurement, therefore, the method can be used for measuring the permeability coefficient of the soil at large scale. In addition, the method can be used for measuring the vertical saturation permeability coefficient of the soil in the water conservancy industry, the hydrogeology industry and the irrigation and water conservancy industry and is easy to be promoted and used.

Description

technical field [0001] The invention relates to a method for measuring soil vertical saturated permeability coefficient, which belongs to the field of hydrological test, in particular to a method for measuring soil vertical saturated permeability coefficient with field portable equipment. technical background [0002] Determination of watershed hydrogeological parameters such as soil permeability coefficient by field tests is of great significance for the study of precipitation infiltration process and watershed runoff law. At present, the commonly used methods for measuring the permeability coefficient in the field include: single / double ring fixed head method, well flow method, suction disk method, etc. However, the above methods have the following defects: (1) a large amount of water injection is required to maintain a constant water head; (2) the measurement scales are relatively small. [0003] In terms of the calculation method of calculating the hydraulic characteris...

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Problems solved by technology

However, the above methods have the following defects: (1) a large amount of water injection is required to maintain a constant water head; (2) the measurement scales are relatively small

However, the Nestingen method has the following conceptual deviations and solution defects: (1) Only three-dimensional infiltration of soil water is considered. In fact, because the single ring is inserted into the soil to a certain depth, the soil water needs to experience one-dimensional infiltration before entering the three-dimensional infiltration. (2) The spherical gap diffusion hypothesis is only valid when the forces acting on the wetting peak are equal in magnitude and are all along the normal direction of the sphere, while the three-dimensional soil infiltration water is under the action of gravity, and the wetting peak is "forced" Therefore, it is necessary to remove the gravity infiltration water from the soil infiltration water by using the spherical defect diffusion hypothesis; (3) the difference dispersion method is used to solve the differential equation, and the numerical calculation results are limited by the accuracy of the measured data, which is likely to cause distortion of the calculation results

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