A Method of Measuring Local Deformation of Dynamic Triaxial Samples of Sand and Gravel Using Electromagnetic Induction Technology

Abstract

The invention provides a measurement method for sand-gravel material dynamic triaxial sample local deformation by utilizing the electromagnetic induction technology, and belongs to the technical fieldof geo-technical testing. By adopting an electromagnetic induction principle, inner local deformation of a triaxial sample is measured based on a middle-sized triaxial apparatus, and granular magnetsin testing equipment are located inside the sample; an annular coil is placed inside a pressure chamber and surrounds the sample; the annular coil is externally connected with a signal amplifier, a filiter and a voltage integrator. The measurement method comprises the steps that a conventional test method is adopted to prepare the sample by using the middle-sized triaxial apparatus, the magnets are embedded, and sample forming is completed; the coil and other equipment are installed and erected; installation, ventilation, saturation and consolidation are carried out on the sample, and the sample is connected with a loading device; under the circumstance of pressurization, calibration is performed on the measuring apparatus for conducting the test, and test data is acquired. According to the method, the structure is reasonable, the assembly is simple, the test operation is convenient and reduces interference on the sample during the test process, and the method can accurately measure the interesting local deformation inside the sand-gravel material triaxial sample.

Description

technical field [0001] The invention belongs to the technical field of geotechnical tests, and relates to a method for measuring the local strain of a geotechnical triaxial test sample, in particular to a method for measuring the local deformation of a dynamic triaxial sample of sand and gravel by using electromagnetic induction technology. Background technique [0002] In the dynamic triaxial test engineering of sand and gravel materials, due to the friction between the rigid sample cap and the base and the sample, the development of axial and lateral deformation of the end of the sample is restricted, while the middle part of the sample is not affected by this. Constrained by friction, as the test progresses, the sample is either pressed into a drum shape or squeezed into a neck shape, and the overall axial strain development of the sample is not uniform enough. At the same time, during the test, the contact surface between the sample loading rod and the sample cap and bet...

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Problems solved by technology

[0006] The purpose of the present invention is to overcome the shortcomings and deficiencies of the prior art and methods, and provide a kind of reasonable structure, simple assembly, convenient test operation and can reduce the interference to the sample in the test process, and can accurately measure the three-axis gravel material at the same time. The method of local deformation of interest inside the sample, which solves the problem of local strain measurement inside the sample body of the dynamic triaxial test of sand and gravel materials and the problem of equipment applicability under the condition of water and pressure

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