Temperature control large-size geotechnical true triaxial multi-field coupling test system and method

Abstract

The invention discloses a temperature control large-size geotechnical true triaxial multi-field coupling test and test method. The system comprises a host loading mechanism, a deformable large-size soil box, an independent three-dimensional loading unit, a refrigeration and water-salt supply unit and a soil-water-ice-salt change monitoring unit; the deformable large-size soil box is arranged on the main machine loading mechanism; and a special structural design is used, a large-size soil sample is divided into an environment soil body area and a core soil area for monitoring, and the size effect of test is eliminated. According to the scheme, the three-dimensional stress state of the soil sample in a three-dimensional open system can be simulated; three-dimensional migration of temperature, moisture, salt and the like among hydrothermal salt evolution, soil body and environment is considered, temperature-moisture-salinity-stress-strain multi-field coupling is achieved, multi-field coupling effect and mutual feedback effect in the open system under the three-dimensional stress state of different engineering geological environments are comprehensively obtained, multifunctionality andcontrollability are realized, the structure is ingenious, and the practical and promotional values are high.

Description

technical field [0001] The invention belongs to the technical field of geotechnical true triaxial tests, and in particular relates to a temperature-controlled large-scale geotechnical true triaxial multi-field coupling test system and a test method. Background technique [0002] The conventional geotechnical triaxial test system is essentially an axisymmetric stress state, which cannot truly reflect the complex stress conditions of the actual soil, and only measures the strength parameters of the soil under the axisymmetric stress state. In order to better and truly simulate the actual stress state of the soil, and analyze the stress, strain and strength characteristics of the soil in the three-dimensional space stress state under the condition of independent changes of the three principal stresses, a true triaxial test system was developed. [0003] According to the loading characteristics of the pressure chamber, the true triaxial test system is divided into three types: r...

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Problems solved by technology

However, the soil samples of the existing true triaxial test devices are all in a completely encapsulated or closed state, which cannot simulate the open state of the actual soil, and there is no way to realize the actual temperature, moisture, and temperature between the soil sample and the environment. The three-dimensional migration process of salt, for example, a multi-field coupling true triaxial test system and its test method disclosed in the invention patent with the application publication number [CN 107576562 A], can be simulated and studied by controlling the stress field and the seepage field Anisotropy of seepage in rock and soil, and simulation research on the physical and mechanical properties of unsaturated soil under multi-field coupling conditions

In addition, the traditional true triaxial test system often uses smaller samples, which are essentially point tests. Because of the small size of the test piece, it is impossible to arrange more sensors (too many sensors have a great impact on the performance of the test piece), and the size of the test piece The effect problem is relatively large, that is, the smaller the specimen, the greater the impact of the scale on the test results, it is difficult to solve the practical problem of multi-field coupling effect

[0004] At present, there is no multifunctional test equipment at home and abroad that considers temperature control, large-scale and multi-field coupling (in practice, most of them are ordinary / temperature-controlled triaxial test systems or small-scale temperature-controlled true triaxial test systems). It is impossible to realize the combined dynamic and static experimental research of multi-field coupling effects such as temperature, moisture, salinity, stress, and strain in engineering geological environments in cold regions

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