Rock long-term strength determination method based on dominant acoustic emission source energy characteristics

A technology of long-term strength and determination method, which is applied in the direction of material analysis, measurement device, and processing detection response signal using acoustic wave emission technology, which can solve the problem of long creep duration and insufficient consideration of rock axial and lateral creep by indirect method Features, poor timeliness and other issues, to achieve the effect of clear physical meaning

Pending Publication Date: 2021-12-31
JIANGXI UNIV OF SCI & TECH
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] (1) The direct method has the limitations of long creep duration and poor timeliness
[0007] (2) The indirect method does not fully consider the relatively obvious difference between the axial and transverse creep characteristics of the rock, an

Method used

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  • Rock long-term strength determination method based on dominant acoustic emission source energy characteristics
  • Rock long-term strength determination method based on dominant acoustic emission source energy characteristics
  • Rock long-term strength determination method based on dominant acoustic emission source energy characteristics

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Experimental program
Comparison scheme
Effect test

Embodiment 1

[0095] 1.1 Preparation of standard rock specimens

[0096] Specimens were prepared according to the "Standards for Test Methods of Engineering Rock Mass" (GB / T50266-2013). Test specimens may be prepared from drilled core or rock blocks. Take a cylinder with a standard diameter of 50mm and a height of 100mm as an example. The instruments and equipment required for specimen preparation include: coring machine, cutting machine, grinding stone machine, etc. Among them, the coring machine is used to drill cores with a diameter of 50mm and a height greater than 100mm. The cutting machine is used to cut the drilled core to obtain a cylindrical core with a diameter of 50mm and a height slightly greater than 100mm. The stone grinding machine is used to grind the end face of the cut cylinder core, and finally prepare a cylinder with a diameter of 50mm and a height of 100mm. In order to ensure the accuracy of the test, the non-parallelism of the two ends of the test piece is less tha...

Embodiment 2

[0177] 2.1 Preparation of standard rock specimens

[0178] Prepare a cylindrical rock specimen with a diameter of 50 mm and a height of 100 mm according to the "Engineering Rock Mass Test Method Standard" (GB / T50266-2013), see Figure 10 .

[0179] 2.2 Acoustic emission source location test in rock creep process

[0180] 2.2.1 Instruments and equipment

[0181] The test loading instrument, that is, the rigid pressure, is the same as the GDS VIS 400kN HPTAS triaxial rheometer. The acoustic emission positioning is completed by the PCI-2 acoustic emission system, and the Nano30 acoustic emission sensor is equipped at the same time. The rock longitudinal wave velocity test adopts the RSM-RCT (B) acoustic wave instrument. For the main equipment, see Figure 11 .

[0182] 2.2.2 Compilation of relative coordinates of standard cylinder

[0183] In order to facilitate the installation and positioning of the acoustic emission sensor and the calculation of the spatial coordinates o...

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Abstract

The invention relates to the technical field of rock physical and mechanical property testing, and discloses a rock long-term strength determination method based on dominant acoustic emission seismic source energy characteristics, which comprises the following steps: carrying out longitudinal wave velocity testing on a standard rock test piece, arranging an acoustic emission sensor on the standard rock test piece; carrying out graded creep failure acoustic emission seismic source positioning test on the standard rock test piece, calculating P wave arrival time and initial motion amplitude corresponding to each acoustic emission seismic source, solving a moment tensor corresponding to each acoustic emission seismic source, classifying the acoustic emission seismic sources according to moment tensor characteristic values, and determining dominant acoustic emission seismic sources; picking up absolute energy of each stage of dominant acoustic emission source, calculating an absolute energy average value of each stage of creep dominant acoustic emission source, and drawing an absolute energy average value-creep stress curve; and taking a creep stress average value corresponding to the lowest point on the absolute energy-creep stress curve and a first data point after the lowest point as a rock average value being long-term strength sigma infinity.

Description

technical field [0001] The invention relates to the technical field of rock physical and mechanical property testing, in particular to a method for determining the long-term strength of rock based on the energy characteristics of the dominant acoustic emission source. Background technique [0002] Rock creep is characterized by the phenomenon that the deformation of rock increases with time under a certain constant load. Engineering practice shows that the failure of rock mass in the underground mining of metal mines is closely related to rock creep properties, and rock creep properties are one of the main factors that induce typical disasters such as roof fall in metal mine stopes and goaf collapse. The strength of rock decreases with the increase of loading time. The long-term strength of rock is defined as the corresponding minimum value of strength when the load action time tends to infinity. Therefore, when the creep stress is less than the long-term strength σ ∞ Whe...

Claims

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Application Information

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IPC IPC(8): G01N29/14G01N29/44
CPCG01N29/14G01N29/4472
Inventor 龚囱王文杰许永斌赵奎曾鹏
Owner JIANGXI UNIV OF SCI & TECH
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