Indoor rock direct shear test device and method capable of providing constant normal stiffness

Abstract

The invention discloses an indoor rock direct shear test device and method capable providing constant normal stiffness. The indoor rock direct shear test device comprises springs and a spring box forproviding the constant normal stiffness and a counter-force fixing device capable of allowing an upper shear box to move vertically in a frictional-resistance-free manner. During a direct shear test,the lower bottom plate of the spring box directly contacts with the test upper shear box, the lower bottom plate can move upwardly along the smooth areas of screws through bolt holes under the effectof vertical force, the spring set is transformed and compressed under the vertical force, and constant normal stiffness can be provided; the counter-force fixing device comprises a bottom plate and asteel shaft, the bottom plate is provided with bolt holes, the bottom plate is connected with the direct shear test device through bolts, two transverse through rails are cut at the top of the steel shaft, balls are placed in the rails, the space of the rails is slightly larger than the balls, the balls contact with the upper shear box and provide horizontal counter force for the upper shear box to allow the upper shear box to slide freely vertically slide in a frictional-resistance-free manner, steel pieces can be demounted, and the cleaning of the rails and the balls can be facilitated.

Description

technical field [0001] The invention belongs to the field of research on the transformation of an indoor direct shear test device, and in particular relates to an indoor rock direct shear test device and a method that can provide constant normal stiffness. Background technique [0002] The shear strength of the rock itself plays an important role in the design of many applications such as rock excavation, rock slope stability analysis and rock-socketed pile design. The shear characteristics of plane rock joints can use traditional direct shear equipment in the laboratory, and the loading method mostly adopts the vertical boundary condition of constant normal force. However, for a shear test where the shear plane is not a plane, with the occurrence of horizontal displacement, the test block will move up and down along the shape of the shear plane. At this time, the normal stress will inevitably increase continuously, while The boundary condition of constant normal force cann...

AI Technical Summary

Problems solved by technology

The invention improves the deficiency that the normal normal stiffness cannot be applied to the upper shear box during the test of the traditional direct shear instrument, and at the same time solves the problem of the side reaction force device when the upper shear box moves vertically with the test block during the direct shear test. Situations that will provide greater frictional resistance and affect test results

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