Size effect of fracture characteristics for anisotropic quasi-brittle geomaterials

Cunbao Li ¹Dongchao Yang ¹Heping Xie ¹Li Ren ²Jun Wang¹

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作者信息

1. Guangdong Provincial Key Laboratory of Deep Earth Sciences and Geothermal Energy Exploitation and Utilization,Institute of Deep Earth Sciences and Green Energy,Shenzhen University,Shenzhen 518060,China;Shenzhen Key Laboratory of Deep Engineering Sciences and Green Energy,College of Civil and Transportation Engineering,Shenzhen University,Shenzhen 518060,China
2. MOE Laboratory of Deep Earth Science and Engineering,Sichuan University,Chengdu 610065,China
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Abstract

Understanding the size effect exhibited by the fracture mechanism of anisotropic geomaterials is impor-tant for engineering practice.In this study,the anisotropic features of the nominal strength,apparent fracture toughness,effective fracture energy and fracture process zone(FPZ)size of geomaterials were first analyzed by systematic size effect fracture experiments.The results showed that the nominal strength and the apparent fracture toughness decreased with increasing bedding plane inclination angle.The larger the specimen size was,the smaller the nominal strength and the larger the apparent fracture toughness was.When the bedding inclination angle increased from 0° to 90°,the effective fracture energy and the effective FPZ size both first decreased and then increased within two complex variation stages that were bounded by the 45° bedding angle.Regardless of the inherent anisotropy of geomaterials,the nominal strength and apparent fracture toughness can be predicted by the energy-based size effect law,which demonstrates that geomaterials have obvious quasi-brittle characteristics.Theoretical analy-sis indicated that the true fracture toughness and energy dissipation can be calculated by linear elastic fracture mechanics only when the brittleness number is higher than 10;otherwise,size effect tests should be adopted to determine the fracture parameters.

Key words

Size effect/Inherent anisotropy/Fracture toughness/Fracture energy/Effective FPZ size/Quasi-brittle geomaterials

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基金项目

National Natural Science Foundation of China(U22A20166)

National Natural Science Foundation of China(51904190)

National Natural Science Foundation of China(12172230)

National Natural Science Foundation of China(11872258)

National Natural Science Foundation of China(U19A2098)

Department of Science and Technology of Guangdong Province(2019ZT08G315)

MOE Laboratory of Deep Earth Science and Engineering(DESE202102)

出版年

2023

矿业科学技术学报(英文版)

中国矿业大学

矿业科学技术学报(英文版)

CSTPCDCSCD北大核心EI

影响因子：1.222

ISSN：2095-2686

被引量2

参考文献量3

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