Device and method achieving triaxial shear tests of samples of different sizes

Abstract

The invention discloses a device and method achieving triaxial shear tests of samples of different sizes. The bottom of a counter-force frame is provided with a power source. The top of the power source is provided with a movable base. The upper portion of the movable base is provided with a lower cushion block. The lower cushion block is provided with a lower water permeable mat. A sample is installed on the top of a lower water permeable plate. The outer surface of the sample is provided with a latex film. The top of the sample is provided with an upper water permeable plate. The top of the upper water permeable plate is provided with an upper cushion block. The top of the upper cushion block is provided with a self-balance ball head device in a positioning mode through an upper positioning pin. An axial force transfer rod penetrates through an upper cover of a confining pressure chamber to make contact with the upper top face of the self-balancing ball head device in a matched mode. An axial sensor is arranged between the axial force transfer rod and the counter-force frame. The test device can achieve triaxial shear tests of samples of different sizes, and the defects that a traditional triaxial test instrument can only test samples of one size and a sealing ring is likely to be damaged due to horizontal sealing are overcome.

Description

technical field [0001] The invention relates to the technical field of geotechnical engineering geotechnical tests, and relates to a test device and a test method for triaxial shear tests of samples of different sizes. Background technique [0002] Triaxial test is one of the most important tests in soil mechanics. It is an indispensable test method for geotechnical engineering workers to investigate the engineering mechanical properties of soil, seek reasonable design parameters, and engage in theoretical research. In the stability calculation of earth dams, slopes and other geotechnical structures, the study of earth pressure and foundation bearing capacity, the widely used failure criterion is the Moore-Coulomb failure criterion, and the triaxial shear test is a Widely used tests that can use the Mohr-Coulomb criterion to solve related parameters; conventional triaxial shear tests and complex triaxial shear tests under different stress paths are important ways to study co...

AI Technical Summary

Problems solved by technology

[0004] (1) The confining pressure chamber and the movable base of the triaxial shear tester are generally connected by bolts. Although bolts can solve the connection problem between the confining pressure chamber and the movable base, they are used in large-scale triaxial shear tests. When installing the instrument, there are generally many bolts, the connection is time-consuming and labor-intensive, and there are unavoidable problems that different bolts are installed with different degrees of tightness.

[0005] (2) During the sample installation process, the sealing measures for the confining pressure chamber and the movable base of the triaxial shear tester are generally placed by placing the sealing ring and the confining pressure chamber in the horizontal plane reserved groove on the movable base. The bottom surface is squeezed and sealed by bolts in the horizontal direction, and there are unfavorable factors such as the soil particles in the horizontal groove are not easy to clean.

[0006] (3) When the triaxial shear test is required for geotechnical engineering materials, the size of the sample in the traditional triaxial shear test is generally a cylinder with a diameter of 300×600mm, 200×400mm, and 150×300mm , and because the traditional indoor triaxial shearing instrument can only test samples of one size (such as 300×600mm), it is necessary to study samples of different sizes (such as 200×400mm) according to the needs of scientific researchers or test programs. A triaxial shear tester with a specific sample size (such as 200×400mm) is required for mechanical properties, sample size effects, etc.

Therefore, the purchase of triaxial shear testers with the same test principle but with different sample sizes has resulted in high operating costs for enterprises, low utilization rate of scientific research funds in universities and research institutes, and a waste of national resources.

[0007] The triaxial shear tester provided by the present invention uses a test device and test method satisfying the triaxial shear test of samples of different sizes, and only needs to utilize the axial loading system and confining pressure of the same triaxial test shearer. The application system, calculation and measurement system overcome the defects that the traditional triaxial tester can only test a sample of one size and the horizontal seal is easy to cause damage to the sealing ring

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