Statistical analysis of thermally induced pre-existing microcracks and their influence on fracture behaviours of granite rock

被引：6

作者：

Li, Yanliang ^{[1
,2
,3
,4
]}

Li, Jiming ^{[1
,3
]}

Ranjith, P. G. ^{[4
]}

Luo, Yongjiang ^{[5
]}

Zhang, Xinxin ^{[6
]}

Yin, Qilei ^{[1
,3
]}

机构：

[1] Jilin Univ, Coll Construct Engn, Changchun 130026, Peoples R China

[2] Jilin Univ, Minist Educ, Key Lab Geoghys Explorat Equipment, Changchun 130026, Peoples R China

[3] Minist Land & Resources, Key Lab Drilling & Exploitat Technol Complex Condi, Changchun 130026, Peoples R China

[4] Monash Univ, Dept Civil Engn, Deep Earth Energy Lab, Bldg 60, Melbourne, Vic 3800, Australia

[5] Chongqing Univ, State Key Lab Coal Mine Disaster Dynam & Control, Chongqing 400044, Peoples R China

[6] Cent South Univ, Sch Geosci & Info Phys, Changsha 410083, Peoples R China

来源：

THEORETICAL AND APPLIED FRACTURE MECHANICS | 2024年 / 134卷

基金：

中国国家自然科学基金;

关键词：

Thermal microcracks; Pre-existing microcracks; Microcrack quantification; Rock strength; Acoustic emission; Fracture mechanism; STRESS-INDUCED MICROCRACKS; CRACK PATTERNS; HARD-ROCK; STRENGTH; QUANTIFICATION; PROPAGATION; EXCAVATION; FAILURE;

D O I：

10.1016/j.tafmec.2024.104722

中图分类号：

TH [机械、仪表工业];

学科分类号：

0802 ;

摘要：

Rocks containing varying degrees of microcracks have a significant influence on their mechanical behavior. Understanding the effect of pre-existing microcracks (PEMs) on rock fracture mechanisms has scientific and practical value in areas such as geothermal energy, nuclear waste disposal and deep mining. We employed a thermally induced approach to create PEMs in granite rock, and quantified characteristic parameters of PEMs by visualization methods, focusing on the quantitative relationships between the PEMs and the mechanical strength and acoustic emission (AE) properties of the rock. We find that the distribution characteristics of thermally induced PEMs obey a lognormal distribution, and the length of individual thermally induced PEMs is almost independent of temperature. The density and orientation of PEMs together determine the variation of the longitudinal wave velocity and rock strength, with the effect of microcrack density dominating. The AE signal suggests that PEMs can affect the fracture behavior and fracture mechanism, depending on the relative dominance of pre-existing and stress-induced microcracks. The AF-RA values show that PEMs lead to an important shift in the fracture mechanism of the rock. When the microcrack density is low, tensile mode dominates the rock failure. Conversely, the shear mechanism dominates the rock fracture.

引用

页数：13