Device for testing hydrothermal variation features of hydrous porous medium in freeze thawing process

Abstract

The invention relates to a device for testing hydrothermal variation features of a hydrous porous medium in a freeze thawing process. The device is characterized in that a double-layer system of internal and external model boxes is adopted, a test sample and a variety of sensors are arranged in the internal model box, the external model box mainly plays a heat preservation and thermal insulation role, refrigerating coils arranged on the inner side wall and at the bottom of the external model box are communicated with two external cold baths to control the temperature and integrally heat and cool, and such liquid with low freezing points as alcohol, kerosene and ethanediol can be placed in the interlayer space of the internal and external model boxes to improve the temperature control precision and the constant temperature effect. The device provided by the invention is mainly used for testing the hydrothermal variation feature parameters of the hydrous porous medium in the freeze thawing process, comprising temperature, volume unfrozen water content, matric suction and the like, so that a water feature curve of the hydrous porous medium in the freeze thawing process is drawn. The device provided by the invention has the advantages of simplicity in operation, stable work, high temperature control precision, high overall heating and cooling speed and the like, data are automatically collected by a data collector, and then the hydrothermal variation feature parameters of the hydrous porous medium in the freeze thawing process are effectively tested and the water feature curve is accurately obtained.

Description

technical field [0001] The invention relates to an experimental test device, in particular to a device for testing the hydrothermal change characteristics of a water-containing porous medium during the freeze-thaw process. The device can realize the overall temperature control and rapid freezing and thawing of the sample, and can effectively measure the hydrothermal characteristic elements of the sample during the freezing and thawing process, such as the change test of temperature, volume unfrozen water content and matrix suction, etc. An effective device for studying the freeze-thaw hydrothermal change characteristics and the freeze-thaw moisture characteristic curve of porous media containing water. Background technique [0002] The freeze-thaw test has a very wide application background in the fields of material frost resistance testing, frost heave prediction of engineering structure foundations in permafrost regions, new drug packaging and transportation, etc. Consi...

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Problems solved by technology

Generally speaking, the similarity between the freeze-thaw cycle and the dry-wet cycle has been verified by experiments and there is no doubt, but the difference between the two is also obvious. The freezing and thawing of aqueous porous media not only involves the phase change of water. , and is often accompanied by the migration of water and solute, the redistribution and unevenness of water in this way will lead to great differences in the suction force of the matrix at different positions, which does not exist in moisture absorption and dehydration, and of course there are dry and wet The mechanism of the hysteresis effect in the cycle process is quite different from the hysteresis effect mechanism in the freeze-thaw process. For example, in addition to the "ink bottle" effect during the freeze-thaw process, the supercooling of water will also cause inconsistencies in the freezing and melting curves.

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