Rock test piece fixture suitable for true triaxial tensile test and use method of rock test piece fixture

Abstract

The invention relates to a rock test piece fixture suitable for a true triaxial tensile test and a use method of the rock test piece fixture. The fixture comprises a normal positioning base, a lower clamping block, an upper clamping block, a left clamping block, a right clamping block, and a pressure conversion tension assembly, wherein the pressure conversion tension assembly is composed of a left pressing plate, a left pulling plate, a right pressing plate, a right pulling plate, and four force-transmitting rods. The method includes the following steps that: a test piece is bonded between the left clamping block and the right clamping block; the clamping surfaces of the lower clamping block and the upper clamping block are coated with a friction reducing material, and the lower clampingblock and the upper clamping block are respectively fastened onto the upper surface and lower surface of the test piece, and the four clamping blocks are bolted to the test piece, so that a combined body can be formed; the front surface and back surface of the test piece are coated with a sealant, and then are dried, bolts on the combined body are removed; the left pulling plate and the left clamping block are fixed together, the right pulling plate and the right clamping block are fixed together, and then, the four force transmitting rods, the left pressing plate and the right pressing plateare sequentially installed; and the normal positioning base is installed on a downward pressing head in a pressure chamber, and the lower clamping block of the combined body is installed onto the normal positioning base, the pressure chamber is closed, and confining pressure, normal stress and tensile stress in the direction of minimum principal stress are applied sequentially until the tensile failure of the test piece occurs.

Description

technical field [0001] The invention belongs to the technical field of rock mechanics experiments, in particular to a rock sample fixture suitable for true triaxial tension experiments and a use method. Background technique [0002] The tensile performance of rock materials is far less than that of compression performance. In the excavation of underground rock mass engineering, most of the rock mass failure is caused by tensile failure, and the tensile failure mechanism directly determines the stability and completeness of rock mass engineering. . [0003] At present, rock tensile tests are mainly divided into uniaxial tensile tests, Brazilian splitting tests and conventional triaxial tensile tests. For the uniaxial tensile test, since the real stress on the rock is mostly three-dimensional stress, and the uniaxial tensile test does not consider the intermediate principal stress and the minimum principal stress at all, the experimental results are difficult to reflect the r...

AI Technical Summary

Problems solved by technology

[0004] Therefore, it is necessary to carry out rock tensile experiments under true triaxial conditions in order to obtain rock tensile mechanical properties closest to the real in-situ stress environment. However, there is currently no rock sample fixture that can meet the requirements of true triaxial tensile experiments.

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