Water-heat-force-displacement experimental system and method of loaded soil under freeze-thaw environment

Abstract

The invention provides a loaded soil body thermo-hydro-mechanical-displacement experiment system and a method at a freezing-thawing environment, and belongs to the field of seasonally frozen soil region subgrade foundation soil body indoor freezing and thawing test. The loaded soil body thermo-hydro-mechanical-displacement experiment system comprises an upper constant temperature unit, a lower constant temperature unit, a constant temperature water supply unit, a bearing barrel, a soil body state monitoring unit, a soil body bearing and loading monitoring unit, an experimental objective table,and a soil body displacement monitoring unit; the upper constant temperature unit is used for freezing or thawing of an experiment soil body top part through freezing or cooling; the lower constant temperature unit is used for maintaining the temperature of soil body bottom to be constant; the constant temperature water supply unit is used for stimulation of underground water supply; the bearingbarrel is used for storing soil body; the soil body state monitoring unit is used for monitoring soil body temperature, water content, internal pressure, and soil body soil water potential; the experimental objective table can be horizontally adjusted. The loaded soil body thermo-hydro-mechanical-displacement experiment system is capable of realizing simulation of soil body freezing thawing experiment process under indoor loading conditions, realizing on-line monitoring on soil body thermo-hydro-mechanical, entire, and layered displacement, and providing support for soil body freezing thawingstudy.

Description

technical field [0001] The invention belongs to the field of indoor freeze-thaw test of subgrade soil in seasonally frozen soil areas, and in particular relates to a water-heat-force-displacement experimental system and method for loaded soil in a freeze-thaw environment. Background technique [0002] Seasonally frozen soil is widely distributed in my country, and its distribution area accounts for about 53.5% of the country's land area. Subgrade foundations built in seasonally frozen soil areas have different forms of damage, such as frost heaving and muddying of subgrades, and uneven settlement of foundations. Although the above damage forms are different, they are all the results of the comprehensive action of soil water, heat and force. [0003] Because the indoor test is low in cost and high in efficiency, and can test a variety of influencing factors, the indoor test is still the main means to study the coupling characteristics of soil water-heat-mechanics. Currently, ...

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Problems solved by technology

[0003] Because the indoor test is low in cost and high in efficiency, and can test a variety of influencing factors, the indoor test is still the main means to study the coupling characteristics of soil water-heat-mechanics. Currently, the indoor soil water-heat-mechanical coupling test unit There have been some related reports. For example, in 2013, Li Haipeng et al. proposed a large-scale high-pressure soil freeze-thaw process water-heat-mechanical coupling experimental system (see Li Haipeng, Hu Chenchen, Song Lei, Wang Rufeng, Zhang Tao, Ren Yanlong, Yang et al. Zhi Jiang. Large-scale high-pressure soil freeze-thaw process water-heat-mechanical coupling experimental system [P]. Jiang CN103116014A, 2013-05-22.), the test unit can apply load to the test soil, but it is Finally, the top of the soil was fixed with an iron plate with limited displacement, so that the frost heave test was carried out in the fixed space of the soil, which limited the displacement of the soil due to frost heaving and thawing, and also had a certain impact on water migration and pressure changes; 2015 Nian Mao Xuesong and others proposed a hydrothermal comprehensive experimental system and test method for soil freezing process (see Mao Xuesong, Hou Zhongjie, Zhang Huijun, Wang Tiequan. Hydrothermal comprehensive experimental system and test method for soil freezing process [P]. Shaanxi: CN104749205A ,2015-07-01.); This experimental system can make the soil free from frost heaving and test related water-thermal-mechanical coupling parameters, but the experimental system does not provide loads for the test soil, it can only be used to study the soil under its own weight Coupling Mechanism of Water-Heat-Mechanism in Freezing Process

[0004] As mentioned above, there is no report showing the temperature change, water migration, pressure change, and the overall and internal displacement of the soil caused by frost heaving and thawing in the freeze-thaw environment of the soil that can apply loads to the upper part. It is a test unit for monitoring, but under general actual engineering conditions, the upper part of the subgrade soil foundation must have a load, and there are frost heave and thaw settlement phenomena when freezing and thawing under the upper load condition, the frost heave or thaw settlement phenomenon It is the result of the comprehensive action of soil water, heat and force, and is manifested by temperature changes, water migration, pressure changes, and displacement changes of the soil.

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