Regular dodecahedron-based three-dimensional stress state testing device and operation method

Abstract

The invention provides a device based on a regular dodecahedron base and six common earth pressure cells. An earth pressure cell groove is formed in the six faces, non-parallel to each other, of the regular dodecahedron base respectively; the six common earth pressure cells are fixed on the six grooves respectively; the gap between each groove and each common earth pressure cell is filled with an expansion water stop ring; a wire hole for guiding a data wire of the common earth pressure cell to the center of the regular dodecahedron is formed in each groove; a wire gathering hole is formed in any face of the regular dodecahedron base without a groove; and the data wire is connected with an earth pressure cell testing and reading element. The invention also provides an operation method of the regular dodecahedron-based three-dimensional stress state testing device. The beneficial effects are as follows: the stress state of a point in an earth body is accurately and conveniently obtained, the error of the traditional way of pasting a strain rosette to reflect stress is improved, and the average test precision is 0.81rho. Through the precision improvement, the conventional stress state of the earth body can be reflected more accurately, and the safety stock of a project is improved.

Description

technical field [0001] The invention belongs to the field of soil stress testing, in particular to a three-dimensional stress state testing device based on a regular dodecahedron and an operation method. Background technique [0002] The thickness of the soil is different and the properties are different, so its stress test is a relatively difficult but basic work. In order to study the strength and deformation of soil in depth, it is first necessary to have a full understanding of the stress state of the soil. In actual engineering constructions such as civil engineering, water conservancy engineering, and environmental engineering, it is of great value to obtain the stress state of the soil directly and accurately for the safety analysis, structural protection and scientific research of the soil. [0003] Currently, stress testing of soils can be done with earth pressure cells and stress gauges. The stress state in a certain direction can be obtained by arranging earth p...

AI Technical Summary

Problems solved by technology

However, it is difficult to measure the Poisson's ratio of the soil under the action of complex forces, and it is difficult to paste the strain rosette on the loose rock and soil, so this method has great defects.

In many engineering practices, it is often necessary to measure the three-dimensional stress state of rock and soil, while conventional stress test components can only test the stress in a single direction, and it is difficult to determine the principal stress direction of the soil, generally only according to the earth pressure box Arranged in the direction parallel to the principal stress direction, and the result of this arrangement method is that the measured value is quite different from the actual value, and the practicability is small

[0004] Usually, the earth pressure cell is buried in the artificially assumed maximum principal stress direction, and the soil has the characteristics of compression deformation and unstable properties, so the measured earth pressure value has no application value

In order to obtain the three-dimensional stress state of a point in the soil, it is possible to embed multiple independent earth pressure cells in the soil, but this method ignores the influence of the interaction between the test data and has a large error

Furthermore, the existing three-dimensional stress testing devices based on rhombic dodecahedral framework and ordinary earth pressure cell, as well as the three-dimensional stress testing device based on octahedral framework and ordinary earth pressure cell, due to the asymmetric geometry of rhombohedral dodecahedron and octahedron As a result, the production process is complicated, and when it is placed in the soil, the center position is not easy to determine, so further improvement is required

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