Midsize direct shear apparatus with non-lever type loading

Abstract

The invention discloses a midsize direct shear apparatus with non-lever type loading, comprising dual rails, a base, a lower shear box, an upper shear box, a pressure transferring plate, a horizontal loading device and a vertical loading device mounted on a beam, wherein the horizontal and vertical loading devices are respectively realized by the way of a stepping motor and a lead screw. Both the load applied to the vertical direction and the load applied to the horizontal direction are measured by a load sensor. The vertical displacement and the horizontal displacement are measured and further controlled by a grating ruler displacement sensor fixed on the lead screw. The shearing area reducing value can be indirectly obtained through the measured value of the vertical displacement and the horizontal displacement, so as to control the loading force of the vertical loading device, that is to say the vertical normal stress can keep a dynamic constant. The direct shear test can more realistically reflect the actual shear strength characteristics of the rock and the soil. Due to the adoption of a transparent toughened glass mode and a matched digital camera, the development change process of the shear surface can be tracked and observed in a real-time manner.

Description

technical field [0001] The invention relates to a device for testing the shear strength and residual shear strength of gravel, soil and soil-rock mixture, in particular to a strain control and stress control type non-lever loading novel medium-sized direct shear instrument. The invention belongs to the technical field of geotechnical experiment testing, and relates to using a stepping motor to load, using a grating ruler to control and measure displacement, realizing stress and strain control, obtaining the shear strength of gravel, soil and soil-rock mixture, and using a Digital image measurement technology to record and observe the development trend of the shear band. [0002] The invention relates to a device for testing soil shear strength, stress and strain behavior, in particular to a strain and stress controlled medium-sized direct shear instrument. Background technique [0003] At present, the direct shear test is a traditional technique for testing the shear streng...

AI Technical Summary

Problems solved by technology

[0005] In order to overcome the deficiency that the shear area of ​​the existing direct shear instrument gradually decreases with the occurrence of the shear displacement during the test process, causing the normal stress to gradually increase with the decrease of the shear area, the problem to be solved by the present invention The technical problem is to provide a medium-sized direct shear apparatus in which the vertical normal stress remains constant during the test

Secondly, in order to solve the deficiencies and defec

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