Tri-axial testing device for testing water content distribution of soil sample

Abstract

The invention discloses a tri-axial testing device for testing the water content distribution of a soil sample. The device comprises a constant current alternating current source, a dynamic voltage tester, a computer and a plurality of groups of sheet electrodes, wherein the sheet electrodes correspond to the layers of the columnar tri-axial soil sample; each group comprises four sheet electrodes which are sequentially adhered to the corresponding layer of the soil sample and a tri-axial membrane at an interval of 45 degrees along the circumferential direction of the corresponding layer of the soil sample; the farthest two sheet electrodes and the middle two sheet electrodes in each group are alternately connected with the two electrodes of the constant current alternating current source and the two input ends of the dynamic voltage tester; the output end of the dynamic voltage tester is connected with the computer. According to the device, the van der Pauw principle is used for dynamically measuring the water content of the soil sample in real time; due to the adoption of the flexible sheet electrodes, the influence on the mechanical properties of the soil sample is avoided, and the testing accuracy of the water content of the soil sample is greatly improved.

Description

technical field [0001] The invention relates to a device capable of accurately testing the change law of water content distribution of soil samples during a triaxial test, and belongs to the technical field of testing. Background technique [0002] During the triaxial test, the test of the water content distribution in the soil sample is very important for the study of the migration and infiltration of water in the soil, and is of great value for the study of the hydraulic-mechanical coupling performance of the soil. For example, the study of the law of water migration in loess is beneficial to prevent the occurrence of loess collapsibility hazards. The test of water migration in frozen soil engineering is the main way to study the mechanism of frost heaving and thawing; especially under the action of dynamics, the test of water infiltration law , which is of great significance for the study of the generation mechanism of subgrade slopping and the design of elimination metho...

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Problems solved by technology

However, this method can only test the water content distribution at the end of the test, and cannot test the changes in the water content distribution during the experiment. It has the disadvantage of being unable to observe dynamically in real time, and cannot grasp the change law

In addition, researchers have also proposed indirect testing methods. These methods mainly use the relationship between the dielectric constant, magnetic permeability and electrical conductivity of the soil sample and the moisture content of the soil sample, and indirectly obtain the soil quality by testing these parameters of the soil sample. However, a common problem in these methods is that the sensor (probe) must be implanted in the soil, and the implantation of the probe in the triaxial test will change the mechanical properties of the soil sample and affect the accuracy of the mechanical test; at the same time, all these The volume of the test method probe is relatively large, and the size is much larger than the triaxial sample itself, so it is impossible to test the moisture content distribution of the triaxial sample

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