Novel triaxial constant load compression and rheological testing machine

Abstract

The invention discloses a novel triaxial constant load compression and rheological testing machine. A motor is adopted to rotationally compress incompressible liquid in a first piston cylinder in order to transmit an axial load to a sample, and a weight is adopted to compress non-air water in a third piston cylinder in order to provide a long-term constant confining pressure. The pressure intensity of the incompressible liquid is controlled, so that the constant output and the monotonous change of the axial load are realized, and the axial load can maintain a certain constant value for a longtime and also can output a rectangular wave cyclic load with a large cycle. When the third piston cylinder for outputting the confining pressure communicates with a second piston cylinder for outputting the axial load, the axial load and the confining pressure are synchronously changed, so that a monotonous loading test and a slow reciprocating cycle load test which are bidirectional and are of the same phase can be realized, and a ratio of the axial load to the confining pressure can be realized through changing the diameter of a hydraulic cylinder. A digital image measuring method adopted bythe deformation measurement of the sample is strong in applicability and high in measuring precision.

Description

technical field [0001] The invention belongs to the technical field of geotechnical testing, and relates to a novel triaxial constant load compression and rheology testing machine. Background technique [0002] Triaxial compression test is one of the conventional geotechnical tests to study the mechanical properties of rock and soil, and it is an important means to construct the stress-strain constitutive model of rock and soil materials and determine their strength. Rock and soil have special engineering characteristics of stress and strain changing with time——rheology, including creep and stress relaxation. Creep characteristics refer to the property that deformation increases with time under the condition of constant force. One of the more concerned problems in soil engineering, such as foundation subsidence, slope and slope instability and other engineering problems are related to the creep of soil. [0003] Triaxial creep test refers to the test in which the axial load...

AI Technical Summary

Problems solved by technology

The improved instrument still uses the lever structure as the force transmission mechanism. During the loading process, the lever is easy to tilt, and the direction of the vertical force will change due to the tilt of the lever. The greater the load applied in the test, the greater the angle between the lever and the horizontal direction. Increase, resulting in the input load and output load ratio (magnification ratio) is not a constant value, so that the loading error is getting bigger and bigger, and the test results have a large deviation

Some motors are used as the power of the rheometer, and the output force is kept constant through the frequent forward and reverse rotation of the motor, which not only seriously affects the service life of the motor, but also requires a complex negative feedback control system

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