Main stress application device for true triaxial apparatus

Abstract

The invention discloses a main stress application device for a true triaxial apparatus. The main stress application device comprises two bases arranged on two sides of a test sample respectively, loading units are arranged on the two bases, can horizontally move on the bases and can vertically extend and retract, the outer side of the loading unit on one side of the test sample contacts with a pressurizing device, the outer side of the loading unit on the other side of the test sample contacts with a counter-force support, and a stress sensor is mounted on the counter-force support. The main stress in a true tri-axis is independently applied, the main stress application device solves the problem that an experimental error is too large as frictional force is too large and soil is squeezed into a gap when the main stress is applied in an overlapping manner by a pressurizing plate in the prior art, and experimental conditions for further analyzing soil mechanical properties in a three-dimensional stress state are created.

Description

technical field [0001] The invention relates to a principal stress applying device in a true triaxial tester. Background technique [0002] At present, various true triaxial instruments used in indoor soil tests can be roughly classified into two categories. The three principal stresses of the first type of true triaxial instrument are not completely independently applied, and the large and medium principal stresses σ 1 , σ 2 is at the small principal stress σ 3 Deviatoric stress is applied on the basis of σ 1 - σ 3 , σ 2 - σ 3 As a result, it is difficult for this type of true triaxial instrument to perform such p Wait q and other special stress path tests. [0003] The second type of true triaxial instrument can apply three principal stresses completely independently. The large, medium and small principal stresses of this type of true triaxial instrument can be freely rotated among the three directions, so various stress path tests can be carried out conv...

AI Technical Summary

Problems solved by technology

But new problems came. First, during the test, due to the small stiffness of the flexible filler, under the axial pressure, part of the soil squeezed into the gap of the pressure plate, forming an uneven contact surface, which increased the pressure on the one hand. The friction between the sample and the pressure plate, on the other hand, hinders the development of the axial deformation of the sample, resulting in the distortion of the test results; secondly, due to the great difference in stiffness between the pressure plate and the filler, it forms a soft and hard surface when it contacts the sample. The staggered contact surfaces form a very complex stress field near the surface of the sample, which is difficult to evaluate the impact on the test results, which is not conducive to the analysis and application of the test results

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