Rock joint sample direct shearing test box

Abstract

The invention relates to a rock joint sample direct shearing test box. The test box comprises a base, an upper shearing box and a lower shearing box which are used for placing a rock joint sample and a normal loading cushion block presses upon an upper joint block of a rock. A fixing support arranged downward is installed on the upper shearing box, a bearing support arranged upward is installed on the lower shearing box, a guiding rod is inserted into the fixing support and the bearing support in a penetrating mode, pin holes are formed in the fixing support, the guiding rod and the fixing support are fixed through a locating pin, and a linear motion bearing used for connecting the guiding rod with the bearing support is arranged in the slot of the bearing support. Compared with the prior art, by means of the test box, not only can free motion of the lower shearing box in the shearing direction in the rock joint sample shearing process be guaranteed, but also the problem that the upper shearing box is reversed upward is effectively solved; contact friction between the upper and lower shearing boxes in the rock joint sample shearing process and friction between the upper shearing box and the upper joint block of the rock are effectively reduced, so that the shearing process is more in line with the real condition.

Description

technical field [0001] The invention relates to geotechnical engineering test equipment, in particular to a rock joint sample direct shear test box. Background technique [0002] The joint plane in rock mass is an important factor controlling the stability of rock mass engineering. The research on its shear mechanical properties has always been the focus of attention in the industry. How to accurately obtain the strength and deformation characteristics of rock joints has become a major issue for technical personnel engaged in rock engineering. greatest difficulty faced. The indoor direct shear test (direct shear test for short) is the most direct and effective means to study the shear mechanical properties of rock mass joints. Traditional rock joint shearing instruments mainly have the following three problems: [0003] 1) During the shearing process of rock joints, especially under high normal load conditions, the upper shear box in the existing direct shear box will move...

AI Technical Summary

Problems solved by technology

[0003] 1) During the shearing process of rock joints, especially under high normal load conditions, the upper shear box in the existing direct shear box will move vertically relative to the lower shear box (upward flipping phenomenon) , changing the stress conditions at both ends of the rock joint, thus affecting the accuracy of the rock joint shear test results;

[0004] 2) During the rock joint shearing process, there will be sliding friction between the inner wall of the upper shear box of the rock joint and the rock joint sample, which makes it difficult to accurately measure the normal dilatancy of the rock joint. The current rock joint shear box usually Apply lubricating oil or place polytetrafluoroethylene gaskets between the inner wall of the upper shear box and the rock joint sample to reduce friction, but the friction reduction effect is not satisfactory;

[0005] 3) During the rock joint shearing process, the upper and lower shear boxes directly contact to generate sliding friction, which makes the shear strength of the rock joints too large, and the lower shear box will also deviate from the shearing direction and move horizontally

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