Triaxial instrument for joint determination of water-air movement in unsaturated soil

Abstract

The invention discloses an unsaturated soil water-gas motion combined determination triaxial apparatus. The triaxial apparatus comprises an actuating system, a seepage pressure chamber and a control system for controlling the actuating system and the seepage pressure chamber, wherein the seepage pressure chamber comprises a frame formed by combining a base, a stand column and a cross beam; a hydraulic mechanism is mounted in the center of the base; the top of the hydraulic mechanism abuts against the bottom of the test piece seat; a confining pressure cylinder which is used for containing a test piece and is provided with a confining pressure air inlet pipe is arranged on the test piece seat; an upper pressure head and a sample holder are respectively arranged at the upper part and the lower part of the confining pressure cylinder; a pressure rod is immovable when axial pressure is applied, an upper pressure head is ejected, argil plates and waterproof breathable films are arranged onthe lower surface of the upper pressure head and the upper surface of the sample holder in a crossed manner, and the argil plates and the waterproof breathable films are respectively connected with water-phase and gas-phase volume and pressure controllers through pressure sensors. The water-gas two-phase permeability coefficient of the soil sample can be measured under the condition of controllingthe matrix suction of the soil sample, and the change characteristics of the matrix suction along the height direction of the soil sample can be quantitatively described.

Description

technical field [0001] The invention relates to electromechanical equipment for geotechnical engineering, in particular to a device for testing the permeability and mechanical properties of unsaturated soil, especially a triaxial instrument for the joint determination of water and air movement in unsaturated soil. Background technique [0002] The theoretical development of unsaturated soil mechanics and its engineering application are inseparable from test equipment. It is necessary to develop test equipment that can accurately test the flow characteristics of water in unsaturated soil and reflect the objective reality of unsaturated soil. The rapid development of soil penetration theory and consolidation theory provides experimental support for its rapid application to engineering practice. Since the water in unsaturated soil is difficult to drain, it is extremely difficult to directly measure its hydraulic conductivity. In recent decades, scholars have put forward variou...

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Problems solved by technology

This patent application controls the confining pressure and air pressure. After the axial load is applied, although the axial load and the axial deformation rate can be measured, and the triaxial test with constant net confining pressure, deviatoric stress and matrix suction can be realized, it cannot Determination of water-air two-phase permeability coefficient of unsaturated soil under the condition of force-water coupling

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