Shear box device for rock indoor direct shear test

Abstract

The invention relates to a rock indoor direct shear test technology, more concretely relates to a shear box device for a rock indoor direct shear test, and belongs to the rock mechanics technical field. The shear box device for the rock indoor direct shear test comprises an upper shear box device and a lower shear box device, a pair of in-line ball rows are provided between the upper shear box device and the lower shear box device, the pair of in-line ball rows are mutually paralleled which are inlaid in the grooves on the top of the front and back wall surfaces of the lower shear box. The shear box device changes a traditional shear box structure, because the upper shear box uses a half-headed mode during the direct shear test, the problem that the width of the shearing seam can not be controlled due to the sample sizes and processing differences is solved, the arrangement of the in-line ball rows realizes the positioning of shear plane of the rock samples and avoids the phenomenon of twist-off but not shear-off of samples. The shear box device of the invention has the advantages of simple structure, easy manufacture, convenient operation and wide application.

Description

technical field [0001] The invention relates to a rock indoor direct shear test technology, more specifically to a shear box device for a rock indoor direct shear test, and belongs to the technical field of rock mechanics. Background technique [0002] Indoor direct shear tests on rocks and structural surfaces usually use the horizontal push method. The rock sample is placed in the lower shear box, the upper shear box is covered on the rock sample, and a certain width is reserved between the upper and lower shear boxes. A normal load is applied to the upper shear box, and a shear load is applied to the lower shear box to cause shear failure of the rock sample and measure its shear strength. [0003] According to the relevant national test specifications, when performing a direct shear test, the acting direction of the normal load and the shear load should pass through the geometric center of the predetermined shear plane of the rock sample. In the current rock laboratory di...

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Problems solved by technology

In the current rock laboratory direct shear test, the upper shear cell is directly covered on the rock sample, and the rock sample will be compressed and deformed under the normal load. In order to ensure that the normal load can be transmitted to the rock sample rather than by The shear box is responsible, and a shear joint of a certain width must be reserved between the upper and lower shear boxes. However, due to differences in the processing of rock samples, the heights of rock samples are different, resulting in the reserved shear joints during different sample tests. The width is different, and the shear load cannot be guaranteed to pass through the geometric center of the predetermined shear plane. In the test, the rock sample is often twisted instead of sheared, resulting in test failure.

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