Test device and use method for surface cracks of expansive soil under the action of hydrothermal and mechanical coupling

Abstract

The invention relates to a device for testing the surface cracks of expansive soil under the action of hydrothermal-mechanical coupling and a method for using the device. The device comprises a model box, a high-strength glass plate, an expansive soil sample, a water supply system, a temperature control system, a loading system and a data acquisition system; The high-strength glass plate is arranged in the model box, and the expansive soil sample is placed on the high-strength glass plate; a plastic ring knife is arranged around the expansive soil sample; the plastic ring knife and the The high-strength glass plates are all transparent structures; the expansive soil samples include expansive soil test samples and parallel test samples; the use method is simple to operate, easy to adjust, and easy to control; the invention realizes the true hydrothermal coupling effect The test of the surface fissures of the lower expansive soil at the same time avoids the damage of the soil sample structure during the test process, improves the accuracy of the test results, realizes the non-damage test, and provides the basis for the hydrothermal-mechanical coupling research of expansive soil.

Description

technical field [0001] The invention relates to the technical field of geotechnical testing of geotechnical engineering, in particular to a device for testing cracks on the surface of expansive soil under the action of hydrothermal-mechanical coupling and a method for using the same. Background technique [0002] Expansive soil is widely distributed in China and is one of the main objects of geotechnical engineering activities. Due to the influence of climate and its own weight or other additional loads, the stress field, moisture field and temperature field in expansive soil are constantly changing, and they influence each other, which is the so-called hydrothermal coupling effect. When the ambient temperature and the water content in the soil change, the expansive soil is prone to expansion and contraction, resulting in cracks, resulting in a sharp decrease in its strength, which has become the main factor affecting the safety of expansive soil engineering. Therefore, it ...

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Problems solved by technology

[0003] However, the current test devices used to study the properties of soil under the hydrothermal coupling effect cannot meet the experimental requirements of the crack test on the surface of expansive soil under the hydrothermal coupling effect.

The main problems are: (1) The coupling of water and heat is a false coupling. The usual practice is to first subject the soil sample to a dry-wet cycle, freeze-thaw cycle, and then load it; although water and heat are coupled in this method, However, in this process, the soil sample has no effect of force. After the soil sample is cured, it is installed in the test device for loading. Therefore, the water, heat and force are applied separately and are not truly coupled; (2) currently Mainly by installing a moisture content sensor and a temperature sensor on the soil sample, the dynamic change of the moisture content and temperature of the soil sample can be obtained; this method will destroy the structure of the soil sample and affect the observation of the cracks in the soil sample

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