Effect of true triaxial principal stress unloading rate on strain energy density of sandstone

Deep rock are often in a true triaxial stress state. Studying the impacts of varying unloading speeds on their strain energy (SE) density is highly significant for predicting rock stability. Through true triaxial unloading principal stress experiments and true triaxial stress equilibrium unloading e...

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Bibliographic Details
Published in:Scientific reports Vol. 14; no. 1; pp. 15172 - 16
Main Authors: Liu, Zhixi, Zhao, Guangming, Meng, Xiangrui, Gu, Qingheng
Format: Journal Article
Language:English
Published: London Nature Publishing Group UK 02.07.2024
Nature Publishing Group
Nature Portfolio
Subjects:
639/166/986
704/2151
Acoustic emission
Coal mining
Damage
Deformation
Energy storage
Engineering
Experiments
Humanities and Social Sciences
multidisciplinary
Rocks
Sandstone
Science
Science (multidisciplinary)
Strain energy density
Stress
Stress state
True triaxial compression
True triaxial unloading principal stress experiments
Unloading
Unloading rate
Strain energy density
Unloading rate
True triaxial unloading principal stress experiments
Damage
True triaxial compression
ISSN:2045-2322, 2045-2322
Online Access:Get full text
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Summary:Deep rock are often in a true triaxial stress state. Studying the impacts of varying unloading speeds on their strain energy (SE) density is highly significant for predicting rock stability. Through true triaxial unloading principal stress experiments and true triaxial stress equilibrium unloading experiments on sandstone, this paper proposes a method to compute the SE density in a true triaxial compressive unloading principal stress test. This method aims to analyze the SE variation in rocks under the action of true triaxial unloading principal stresses. Acoustic emission is used to verify the correctness of the SE density calculation method in this paper. This study found that: (1) Unloading in one principal stress direction causes the SE density to rise in the other principal stress directions. This rise in SE, depending on its reversibility, can be categorized into elastic and dissipated SE. (2)When unloading principal stresses, the released elastic SE density in the unloading direction is influence by the stress path and rate. (3) The higher the unloading speed will leads to greater increases in the input SE density, elastic SE density, and dissipative SE density in the other principal stress directions. (4) The dissipated SE generated under true triaxial compression by unloading the principal stress is positively correlated with the damage to the rock; with an increase in unloading rate, there is a corresponding increase in the formation of cracks after unloading. (5) Utilizing the stress balance unloading test, we propose a calculation method for SE density in true triaxial unloading principal stress tests.
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ISSN:2045-2322
2045-2322
DOI:10.1038/s41598-024-66185-9