Testing method for one-time measurement of tensile modulus and compression modulus of rock

Abstract

A testing method for one-time measurement of the tensile modulus and the compression modulus of rock comprises steps as follows: a horizontal strain gauge and a vertical strain gauge are pasted at centers of front and back sides of a disk sample respectively; the disk sample is placed on a press for a Brazilian disk test, the load force P is monitored by a pressure sensor, and the horizontal strain gauge and the vertical strain gauge monitor transverse strain epsilon x and vertical strain epsilon y of the centers of the disk sample respectively; the tensile modulus and the compression modulus of the rock are calculated as per the following formulas shown in the specification, wherein Ex and Ey represent the tensile modulus and the compression modulus of the rock respectively, P is the external load, D is the disk diameter, L is the disk thickness, vyx represents the x-direction transverse deformation coefficient caused by y-direction stress, and epsilon x and epsilon y represent the transverse strain and the vertical strain of the disk centers respectively. The tensile modulus and the compression modulus of the rock can be measured on the same rock sample through one test, the test method is simple and easy to implement, data are accurate and reliable, and results are more scientific.

Description

technical field [0001] The invention belongs to the field of rock mechanics, in particular to a test method for one-time measurement of rock tensile modulus and compressive modulus. Background technique [0002] Under the action of load, the first physical phenomenon that occurs in rock is deformation. As the load increases, the deformation of rock gradually increases, and eventually failure occurs. Therefore, the deformation capacity of rock is one of its most important mechanical properties. Rock deformation parameters are usually expressed by elastic modulus and Poisson's ratio. The resistance to compression deformation; Poisson's ratio refers to the ratio of the absolute value of the transverse strain to the axial strain when the material is under unidirectional tension or compression, which reflects the transverse deformation capacity of the material. [0003] The theoretical basis for testing rock deformation parameters comes from the theory of elastic mechanics. The...

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Problems solved by technology

[0005] Some scholars have used Brazilian discs to study the tensile properties of rocks, but studies have shown that the tensile modulus and compressive modulus of rocks are often different. The stress-strain relationship can be measured by uniaxial tension and compression tests, respectively. The tensile modulus and compressive modulus of rock, but there are the following problems: first, there are technical difficulties in the direct tensile test, which leads to large errors and even test failure; second, the properties of the same rock sample often have different It is not scientific enough to compare the tensile modulus and compression modulus measured by different specimens, and it is impossible to obtain the tensile modulus and compression modulus of the same sample

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