Miniature three-dimensional earth pressure cell and its testing method

Abstract

The invention provides a miniature three-dimensional soil pressure box. The center of each surface of a rhombic dodecahedron framework of the soil pressure box is respectively provided with a circular hole. A rhombic elastic diaphragm is arranged on each rhombic surface of the rhombic dodecahedron framework, so that the inner walls of all rhombic elastic diaphragms form circular surfaces. Resistance strain gauges are attached onto four top circular surfaces and two adjacent circular surfaces of the rhombic dodecahedron framework. A data wire hole is formed in any rhombic surface of the bottom of the rhombic dodecahedron framework. The wires of the resistance strain gauges are led out of the data wire hole to be connected with a data acquisition instrument. Gaps among the rhombic elastic diaphragms and the rhombic dodecahedron framework are firmly filled with a waterproof sealant so as to form the miniature three-dimensional soil pressure box. Meanwhile, the invention provides a test method of the miniature three-dimensional soil pressure box. According to the technical scheme of the invention, the advantages of diversified dimension, distinct principle, wide applicability, simple structure, low manufacturing cost, high precision and the like are realized. Therefore, a guarantee for directly testing the stress state of a certain point in the soil body is provided.

Description

Technical field [0001] The invention belongs to the field of conventional stress testing, in particular to a miniature three-dimensional soil pressure box and a testing method thereof, and is suitable for the field of geotechnical engineering. technical background [0002] The earth pressure measuring device is an important equipment for carrying out soil tests and determining the mechanical parameters of the soil. The accuracy of its measurement directly affects the correct understanding of the soil. At present, the conventional equipment for testing soil stress is an earth pressure cell, which is divided into single-membrane and double-membrane earth pressure cells according to different forms of force transmission. When the load acts on the soil, the stress is transferred to the earth pressure cell. A resistance strain gauge or steel string is arranged on the pressure side of the earth pressure cell to measure the deformation of the pressure surface of the earth pressure cell ...

AI Technical Summary

Problems solved by technology

[0003] Conventional stress devices can only measure the stress in a certain direction in the soil; CN201410740140.2 discloses research results based on three-dimensional strain rosettes that can obtain the strain state inside the soil. Due to the complex characteristics of the soil, its Poisson's ratio It is difficult to determine the isoelastic-plastic parameters, so there are great defects in calculating the three-dimensional stress state inside the soil by using the strain state

CN201410345195.3 and CN201510956800.5 etc. disclose a kind of three-dimensional earth pressure state testing device based on rhombic dodecahedron and other bases. Because the earth pressure cell is attached to the base, the earth pressure cell size determines the soil pressure state. The volume of the pressure test device is too large, thus affecting the test accuracy of the stress state

[0004] The above problems often cause a certain difference between the test results and the real value, resulting in an inaccurate understanding of the three-dimensional stress state of a point in the soil

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