Direct shear tester for testing strength of slip band and direct shear test method

Abstract

The invention discloses a direct shear tester for testing the strength of a slip band and a direct shear test method, and solves the technical problem that the residual strength of the slip band of a large-size geotechnical material is difficult to obtain by the existing tester and test method. The direct shear tester comprises shear boxes, a horizontal loading system, a normal loading system and a measuring system, wherein the opening area of the lower shear box is larger than that of the upper shear box, and the normal loading system adopts a mechanical lever principle to load normal stress on multiple amplification effects of force. The normal loading system specifically comprises n stages of amplification lever groups, the n stages of amplification lever groups comprise n amplification lever mechanisms with the ratio of power arms to resisting arms being greater than 1, and the resisting arm of the ith stage of amplification lever mechanism acts on the power arm of the (i+1)th stage of amplification lever mechanism, so that step-by-step amplification of the load can be realized; a power arm and / or a resisting arm of at least one amplification lever mechanism in the n stages of amplification lever sets can be adjusted, and continuous loading of normal force can be achieved.

Description

technical field [0001] The application belongs to the technical field of geotechnical tests, and in particular relates to a direct shear tester for testing the strength of a sliding belt and a direct shear test method. Background technique [0002] Accumulative landslides refer to a typical type of landslides where Quaternary and modern loose accumulations are unstable, and are widely distributed in the Three Gorges Reservoir area and Southwest provinces in my country. Taking the Three Gorges Reservoir area in eastern Chongqing and western Hubei as an example, among all types of landslides, accumulative layer landslides account for a large proportion. Only accumulative layer landslides accounted for 80%. [0003] Accumulative landslides have special material composition and structural characteristics. Taking reservoir accumulative landslides as an example, it usually shows that the upper landslide loose rock and soil slides along the underlying bedrock interface, and the de...

AI Technical Summary

Problems solved by technology

[0005] There are following defects in the existing test instrument for implementing the above-mentioned sliding band strength testing method: (1) direct shear instrument has limited shear distance during shear test, thereby being difficult to carry out the test of residual strength; (2) ring shear instrument although Unlimited ultra-long-distance shearing can be carried out in one direction, but its structural characteristics determine the uneven distribution of shear stress and strain along the radial direction of the shear surface, and the small size of the ring shear device limits the size of the sample gravel. (3) The shear distance provided by the triaxial tester is small. Although it can be used for peak strength testing, it is also difficult to carry out residual strength testing.

[0006] In recent years, although some geotechnical testing instruments have emerged to test the residual strength of soils that overcome the limitations of shear distance and sample size, there are still few suitable instruments to solve the problem of special slip zones (gravel soil-base) rock interface), so it is necessary to make further innovations in this field

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