A test method for one-time measurement of rock tensile modulus and compressive modulus

Abstract

A test method for one-time measurement of rock tensile modulus and compressive modulus, comprising sticking horizontal strain gauges and vertical strain gauges respectively at the center of the front and back of a disc sample; placing the disc sample on a press, Carry out the Brazilian disk test, use the pressure sensor to monitor the loading force P, and use the horizontal strain gauge and vertical strain gauge to monitor the transverse strain εx and vertical strain εy in the center of the disc sample respectively; the tensile modulus of the rock can be calculated by the following formula and compression modulus: E y = 2 P πDL 3 + ν yx ε y - - - ( 1 ) E x = 2 P πDL 3 + ν yx ( 3 + ν yx ) ε x + 3 ν yx ε y - - - ( 2 ) where Ex and Ey represent the tensile modulus and compressive modulus of the rock, respectively, P is the external load, D is the diameter of the disk, L is the thickness of the disk, νyx represents the lateral deformation coefficient in the x direction caused by the stress in the y direction, εx and εy denote the transverse strain and vertical strain at the center of the disc, respectively. The tensile modulus and compressive modulus of the rock can be measured on the same rock sample through one test. The test method is simple and feasible, the data is accurate and reliable, and the result is 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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