Simulation method for crack subcritical expansion fracture energy of rock double-twist test piece

A simulation method and fracture energy technology, applied in the direction of using stable torsion to test material strength, using stable tension/pressure to test material strength, instruments, etc., can solve the difference of rock heterogeneity, the test loading method is complex and irreversible and other problems to achieve the effect of avoiding engineering instability and damage, saving labor costs and time costs

Active Publication Date: 2021-06-01
SHANDONG UNIV
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Problems solved by technology

However, the current double torsion test has the following difficulties: (1) It is very difficult to process brittle rock into an extremely thin plate with a thickness of 3-5mm
(2) The h

Method used

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  • Simulation method for crack subcritical expansion fracture energy of rock double-twist test piece
  • Simulation method for crack subcritical expansion fracture energy of rock double-twist test piece
  • Simulation method for crack subcritical expansion fracture energy of rock double-twist test piece

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Embodiment 1

[0037] In a typical implementation of the present disclosure, such as Figure 1-Figure 4 As shown in Fig. 1, a method for simulating the fracture energy of crack subcritical propagation in rock double torsion specimens is proposed.

[0038] Include the following steps:

[0039] Make rock material standard samples and conduct tests to obtain rock material mechanical parameters;

[0040] Make double-torsion specimens and conduct tests to obtain the load relaxation rate and failure load of the specimens;

[0041] Establish the extended finite element model of the double torsion test piece and preset notches and cracks, and substitute the obtained rock material mechanical parameters, load relaxation rate and failure load into the extended finite element model;

[0042] Load the extended finite element model to obtain the preset crack initiation time;

[0043] Define the interaction between cracks, calculate the energy release rate of the crack tip of the double torsion specimen...

Embodiment 2

[0070] In another typical implementation of the present disclosure, as shown in the figure, a method for simulating the crack propagation fracture energy of a rock double torsion specimen is proposed.

[0071] On the basis of Embodiment 1, a set of detailed processes are provided in this embodiment, including the following steps,

[0072] Step 1: Use granite material to make a standard test block, and test its compressive strength and tensile strength;

[0073] In this step, the mechanical parameter test adopts the existing mechanical parameter test process, which will not be repeated here.

[0074] Step 2: Use the granite material used in step 1 to make a test piece, and process it into a double-torsion test piece with a size of 180mm×60mm×5mm. On the bottom side of the center of the test piece along the length direction, process a V-shaped guide groove with a width of 4 mm and a depth of 2.5 mm along the direction of the slit, and process a slit with a length of 10 mm to ma...

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Abstract

The invention provides a simulation method for crack subcritical expansion fracture energy of a rock double-twist test piece, and relates to the technical field of rock subcritical crack expansion. The method comprises the steps of manufacturing and testing a rock material standard sample, and obtaining rock material mechanical parameters; manufacturing and testing the double-twist test piece, and obtaining the load relaxation rate and the failure load of the test piece; establishing a double-twist test expansion finite element model, presetting gaps and cracks, and substituting the obtained rock material mechanical parameters, the load relaxation rate and the failure load into the expansion finite element model; loading the expansion finite element model to obtain preset crack initiation time; defining the interaction between cracks, calculating the crack tip energy release rate of the double-twist test piece, and obtaining the crack tip energy release rate at the crack initiation moment of the preset cracks as the critical energy release rate; and carrying out simulation and application according to the rock material mechanical parameters and parameters obtained by a double-twist test, so that the fracture energy is obtained, and data support is provided for research on avoiding subcritical crack expansion of rock.

Description

technical field [0001] The present disclosure relates to the technical field of rock subcritical crack growth, in particular to a method for simulating fracture energy of crack subcritical growth in rock double torsion specimens. Background technique [0002] The statements in this section merely provide background information related to the present disclosure and may not necessarily constitute prior art. [0003] Various examples of engineering instability related to rock mass show that the expansion and development of cracks in rock mass is one of the main causes of engineering instability and damage. When the crack contains oxides and silicates, when the stress intensity factor at the crack tip is much lower than the fracture toughness, the crack will still expand at a certain speed. Many factors related to the environment (such as stress corrosion, etc.) lead to such expansion. This stable, quasi-static crack growth is called subcritical growth. [0004] The inventors...

Claims

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Application Information

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IPC IPC(8): G01N3/08G01N3/22
CPCG01N3/08G01N3/22G01N2203/0003G01N2203/0017G01N2203/0019G01N2203/0021
Inventor 韩勃张柏楠李维国
Owner SHANDONG UNIV
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