Multi-field coupling true triaxial test system and experiment method implemented by same

Abstract

The invention discloses a multi-field coupling true triaxial test system and an experiment method implemented by the same. The multi-field coupling true triaxial test system is characterized by comprising a true triaxial double-cavity pressure chamber (1), an axial loading system (2), a confining pressure/back pressure loading system (3), a temperature control system (4), a permeation control system (5), a gas loading system (6), a bending element experiment system (7) and a computer (8). The multi-field coupling true triaxial test system and the experiment method have the advantages that stress fields and seepage fields are controlled, and accordingly simulation research can be carried out on seepage anisotropy of rock and soil mass; influence of environmental factors on freezing nucleusor frozen soil samples can be simulated under the effects of temperature fields, the seepage fields and the stress fields; research can be carried out on the physical and mechanical properties of unsaturated frozen soil under the effects of the temperature fields and the stress fields; simulation research can be carried out on change of the physical and earth properties of sediments in generationand decomposition procedures of natural hydrates under multi-field coupling conditions, and simulation research can be carried out on mutual displacement effects between hydrate gas in the sediments and underground water; simulation research can be carried out on the physical and mechanical properties of unsaturated soil under the multi-field coupling conditions.

Description

technical field [0001] The invention relates to a multi-field coupling true triaxial test system and its test method, in particular to a test method for indoor test research of complex working conditions under the action of multi-field coupling, providing theoretical basis and test for engineering practical application and theoretical research in accordance with. Background technique [0002] At present, in the multi-field coupling test research of rock and soil materials, there are many disadvantages as follows: [0003] 1. The test system mostly uses the conventional triaxial instrument as the supporting equipment to control the stress and strain of the sample, but the horizontal loading provided by the conventional triaxial instrument during the test is equal stress loading, that is, the middle principal stress σ 2 equal to the minor principal stress σ 3 , but cannot simulate complex working conditions, which limits the loading control of the stress state in the test; ...

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Problems solved by technology

[0003] 1. The test system mostly uses the conventional triaxial instrument as the supporting equipment to control the stress and strain of the sample, but the horizontal loading provided by the conventional triaxial instrument during the test is equal stress loading, that is, the middle principal stress σ 2 equal to the minor principal stress σ 3 , but cannot simulate complex working conditions, which limits the loading control of the stress state in the test;

[0004] 2. Due to the anisotropy of the soil structure, the physical performance indicators of the soil are different in all directions during the stress deformation process, especially the isotropic permeability characteristics of the soil. Usually in the indoor seepage field test, the existing test Most of the equipment is controlled by osmotic pressure and osmotic flow in a single direction in the vertical direction. Based on this, the anisotropic difference test of the permeability is mainly performed by osmotic loading on the fabricated vertical and horizontal samples. The vertical and horizontal permeability coefficients thus obtained often reduce the accuracy and rationality of the test results because they deviate from engineering reality and ignore the interaction of multi-directional seepage;

[0005] 3. In the temperature field control of the indoor test, the existing test equipment mostly uses resistance wire or circulating water bath system for temperature control, and uses thermal insulation materials to insulate the equipment and the external environment. Due to the control of heating equipment such as resistance wire Accuracy problems and the limitations of the insulation material itself often show the low accuracy of the test temperature control and the temperature gradient phenomenon in the test environment, which affects the accuracy and effectiveness of the test temperature field control;

[0006] 4. In the development and application research of new energy, due to the storage method and development needs of new energy, it is necessary to conduct a series of experimental studies on the new energy storage medium - rock and soil materials, but due to the chemical properties of new energy, and It is difficult to find a test system that can meet the needs of rock and soil media containing new energy in existing indoor test equipment

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