A modified 3D mean strain energy density criterion for predicting shale mixed-mode Ⅰ/Ⅲ fracture toughness

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外文摘要：The fracture toughness of rocks is a critical fracturing parameter in geo-energy exploitation playing a significant role in fracture mechanics and hydraulic fracturing.The edge-notched disk bending(ENDB)specimens are employed to measure the entire range of mixed-mode Ⅰ/Ⅲ fracture toughness of Longmaxi shale.To theoretically interpret the fracture mechanisms,this research first introduces the detailed derivations of three established fracture criteria.By distinguishing the volumetric and distortional strain energy densities,an improved three-dimensional mean strain energy density(MSED)criterion is pro-posed.As the critical volumetric to distortional MSED ratio decreases,the transition from tension-dominated fracture to shear-dominated fracture is observed.Our results indicate that both peak load and applied energy increase significantly with the transition from pure mode Ⅰ(i.e.,tension)to pure mode Ⅲ(i.e.,torsion or tearing)since mode-Ⅲ cracking happens in a twisted manner and mode-Ⅰcracking occurs in a coplanar manner.The macroscopic fracture signatures are consistent with those of triaxial hydraulic fracturing.The average ratio of pure mode-Ⅲ fracture toughness to pure mode-Ⅰfracture toughness is 0.68,indicating that the obtained mode-Ⅲ fracture resistance for a tension-based loading system is apparent rather than true.Compared to the three mainstream fracture criteria,the present fracture criterion exhibits greater competitiveness and can successfully evaluate and predict mixed-mode Ⅰ/Ⅲ fracture toughness of distinct materials and loading methods.

外文关键词：

Longmaxi shaleHydraulic fracturingFracture mechanismsFracture criteriaMixed-mode Ⅰ/Ⅲ fracture toughnessEdge-notched disk bending

作者：

Kun Zheng、Chaolin Wang、Yu Zhao、Jing Bi、Haifeng Liu

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作者单位：

College of Civil Engineering,Guizhou University,Guiyang,550025,China

State Key Laboratory of Geomechanics and Geotechnical Engineering,Institute of Rock and Soil Mechanics,Chinese Academy of Sciences,Wuhan,430071,China

基金：

National Natural Science Foundation of ChinaNational Natural Science Foundation of ChinaNational Natural Science Foundation of China

项目编号：

523640045226400652164001

出版年：

2024

DOI：

10.1016/j.jrmge.2023.09.016

岩石力学与岩土工程学报(英文版)

中国科学院武汉岩土力学所中国岩石力学与工程学会武汉大学

岩石力学与岩土工程学报(英文版)

CSTPCD

影响因子：0.404

ISSN：1674-7755

年,卷(期)：2024.16(7)