Directional low friction based large indoor self-balancing direct shear instrument and working method thereof

Abstract

The invention relates to a directional low friction based large indoor self-balancing direct shear instrument. The directional low friction based large indoor self-balancing direct shear instrument comprises an upper shearing box and a lower shearing box for holding soil samples, the upper shearing box has no bottom cover, the lower shearing box has no top cover, and the bottom of the upper shearing box is supported at the top of the lower shearing box through a first roller and is driven by a horizontal loading jack to do translational movement in the shearing direction; a shearing box coverplate, driven by a vertical loading jack to move up and down, is arranged at the inner top of the upper shearing box; the top of the vertical loading jack does translational movement on the frame plane above the vertical loading jack in the shearing direction through a second roller. The directional low friction based large indoor self-balancing direct shear instrument has a simple structure.

Description

technical field [0001] The invention relates to a directional low-friction self-balancing large-scale indoor direct shear instrument and a working method thereof, belonging to the field of geotechnical engineering measuring equipment. Background technique [0002] In the field of geotechnical engineering, shear failure is the main mode of soil instability, and it is particularly important to accurately measure the shear strength index of soil in geotechnical engineering construction. Commonly used shear strength index measurement methods include: in-situ cross plate test, in-situ large-scale direct shear test, indoor triaxial compression test, indoor small-scale direct shear test, etc. Among them, the indoor small direct shear instrument has the advantages of simple structure and convenient operation, and is widely used. [0003] However, the conventional small indoor direct shear instrument is limited by its own size and cannot truly reflect the size effect of the shear st...

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Problems solved by technology

[0003] However, the conventional indoor small direct shear instrument is limited by its own size and cannot truly reflect the size effect of the shear strength of the soil, let alone measure the shear strength of soil samples containing gravel.

If the indoor direct shear instrument is enlarged, at least the following problems need to be overcome: the friction between the upper and lower boxes will offset part of the shear force, making the test results inaccurate; The direction of the shear force is not easy to control (prone to eccentricity); a large counter force device is required to provide large normal force and shear force

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