True triaxial instrument of deformation without side direction interference

Abstract

The invention discloses a true triaxial apparatus without pressure cell structure, of which deformation is free from side interference, and the true triaxial apparatus is applicable to the true triaxial test of soil samples comprising coarse-grained soil and fine-grained soil. A rigid plate is used to pressurize in vertical direction, the bottom surface of the rigid plate and the top surface of the base are respectively provided with a roller for preventing side interference; rigid and flexible mixed blocks which are composed of metal plates and hollow rubber pipes in an alternating manner are used to pressurize in the front-rear direction, the true triaxial apparatus can be compressed along with the sample driven by the rollers in the vertical direction but in the horizontal direction; and a flexible water pocket structure is used to pressurize in left-right direction. The deformations of the sample in three directions can be obtained by the conversion calculation of the rotation circle-number of the motor in the corresponding direction, thus the accuracy is higher. The true triaxial apparatus can be used for the test of stress path in three-dimensional stress space, and the side interference can be efficiently avoided when the deformation of the sample is relatively obvious.

Description

Technical field [0001] The invention relates to a geotechnical test instrument, in particular to a true triaxial instrument that provides samples with unequal stress conditions and is free from lateral interference after deformation. Background technique [0002] When studying the mechanical properties of the soil under the three-dimensional unequal stress state, a true triaxial apparatus is required. Existing true triaxial instruments can be roughly divided into two categories: One is the use of pressure chambers. The large, medium, and small principal stresses of this type of true triaxial instrument are not completely applied independently. The large and medium principal stresses σ 1 , Σ 2 Is at the small principal stress σ 3 (Pressure chamber pressure) separately apply "deviatoric stress" σ 1 -σ 3 , Σ 2 -σ 3 Obtained; the other type is to use no pressure chamber, set three completely independent pressure systems in the three principal stress directions of the sample, the larg...

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Problems solved by technology

Existing true triaxial instruments can be roughly divided into two categories: one is the use of pressure chambers, the large, medium, and small principal stresses of this type of true triaxial instrument are not applied completely independently, and the large and medium principal stresses σ 1 , σ 2 is the small principal stress σ 3 On the basis of (pressure chamber pressure), respectively apply "deviator stress" σ 1 -σ 3 , σ 2 -σ 3 The other type is to set three completely independent pressurization systems in the three principal stress directions of the sample without using a pressure chamber. The large, medium and small principal stress σ of this type of instrument 1 , σ 2 , σ 3 It can be freely rotated among the three directions, so various stress path tests can be conveniently carried out, but the defect of this type of true triaxial instrument is that the pressure systems in the three directions are easy to interfere with each other and the deformation of the sample is easily affected by the side. Interference

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