Study on the influence mechanism of porosity on the mechanical properties, deformation and failure characteristics of coal samples

被引：0

作者：

Li, Jianzhong ^{[1
,2
,3
]}

Wei, Jiong ^{[1
,2
]}

Yuan, Guiyang ^{[1
,2
]}

Shi, Yao ^{[1
,2
]}

机构：

[1] State Key Laboratory of Intelligent Coal Mining and Strata Control, Beijing

[2] CCTEG Coal Mining Research Institute, Beijing

[3] School of Energy and Mining Engineering, China University of Mining and Technology(Beijing), Beijing

来源：

Journal of Mining and Strata Control Engineering | 2024年 / 6卷 / 03期

关键词：

mechanical properties; microscopic cracks; numerical simulation; porosity; tension stress;

D O I：

10.13532/j.jmsce.cn10-1638/td.20240519.001

中图分类号：

学科分类号：

摘要：

To elucidate the impact of porosity on the mechanical properties and deformation failure characteristics of coal samples, numerical simulations of uniaxial compression on coal samples of varied porosities were conducted using UDEC-Trigon. The mechanical properties and deformation failure characteristics of coal samples with different porosities were investigated, exploring the impact of porosity on macroscopic deformation failure, microscopic crack development and acoustic emission evolution.The results show that increasing porosity result in an exponential decrease in the uniaxial compressive strength (UCS) and residual strength of coal samples. The elastic modulus and deformation modulus gradually decreased, while Poisson's ratio showed a gradual increase. Under the influence of porosity, internal microscopic tensile cracks in coal samples were more prone to initiation, expansion and coalescence. With the increase of porosity, the instability of coal samples transitioned from tensile-shear brittle failure to tensile ductile failure, facilitating the formation of macroscopic cracks and significantly increasing their quantity and distribution range. Porosity-induced changes shifted the acoustic emission signals of coal sample from sudden and rapid evolution to a slower evolution. Tensile stress at the tip of pores drove the initiation and extension of microscopic tensile cracks. Higher porosity led to a broader distribution range and increased magnitude of tensile stress, resulting in numerous microscopic cracks initiation, propagation, and coalescence and leading to a larger extent of coal sample failure and an increased number of macroscopic cracks. The distribution and evolution of tensile stress within coal samples were significantly influenced by the characteristics of pore structure, which influencing the initiation, extension, and coalescence of microscopic cracks at pore tips. This research provides guidance for mine roadway drilling pressure relief to prevent rock bursts. © 2024 Editorial Office of Journal of Mining and Strata Control Engineering. All rights reserved.

引用

共 27 条

[1]

XIE Heping, Introduction to fractals in rock mechanics, (1996)

[2]

JU Y, YANG Y M, SONG Z D, Et al., A statistical model for porous structure of rocks[J], Science in China (Series E), 51, 11, pp. 2040-2058, (2008)

[3]

JU Y, YANG Y M, MAO Y Z, Et al., Laboratory investigation on mechanisms of stress wave propagations in porous media[J], Science in China(Series E), 52, 5, pp. 1374-1389, (2009)

[4]

PALCHIK V., Influence of porosity and elastic modulus on uniaxial compressive strength in soft brittle porous sand-stones[J], Rock Mechanical and Rock Engineering, 32, 4, pp. 303-309, (1999)

[5]

VERNIK L, BRUNO M, BOVBERG C., Empirical relations between compressive strength and porosity of siliclassic rocks[J], Int J Rock Mech Min Sic & Geomech Abstr, 30, 7, pp. 677-680, (1993)

[6]

WANG Baoshan, CHEN Yu, GE Hongkui, Et al., A discrete element model of porous rock deformation[J], Chinese Journal of Geophysics, 48, 6, pp. 1336-1342, (2005)

[7]

ZHOU Wei, YANG Hongxia, Effects of fractures of rock on elastic property of rock and velocity-porosity relation[J], Oil Geophysical Prospecting, 40, 3, pp. 334-338, (2005)

[8]

SMITH T M, SAYERS C M, SONDERGELD C H., Rock properties in low-porosity/low-permeability sand-stones [J], Society of Exploration Geophysicists, 28, 1, pp. 48-59, (2009)

[9]

CLAVAUD J B, MAINEULT A, ZAMORA M., Permeability anisotropy and its relations with porous medium structure, Journal of Geophysical Research(Part B), 113, B1, pp. 1202-1212, (2008)

[10]

LI Chuanliang, The Relationship between rock compressibility and porosity, China Offshore Oil and Gas, 17, 5, pp. 355-358, (2003)

← 1 2 3 →