Size effect of fracture characteristics for anisotropic quasi-brittle geomaterials

作     者：Cunbao Li Dongchao Yang Heping Xie Li Ren Jun Wang Cunbao Li;Dongchao Yang;Heping Xie;Li Ren;Jun Wang

作者机构：Guangdong Provincial Key Laboratory of Deep Earth Sciences and Geothermal Energy Exploitation and UtilizationInstitute of Deep Earth Sciences and Green EnergyShenzhen UniversityShenzhen 518060China Shenzhen Key Laboratory of Deep Engineering Sciences and Green EnergyCollege of Civil and Transportation EngineeringShenzhen UniversityShenzhen 518060China MOE Laboratory of Deep Earth Science and EngineeringSichuan UniversityChengdu 610065China 

出 版 物：《International Journal of Mining Science and Technology》 (矿业科学技术学报（英文版）)

年 卷 期：2023年第33卷第2期

页      面：201-213页

核心收录：

学科分类：08[工学] 0807[工学-动力工程及工程热物理] 080104[工学-工程力学] 0815[工学-水利工程] 0801[工学-力学（可授工学、理学学位）] 

基　　金：the National Natural Science Foundation of China(Nos.U22A20166,51904190,12172230,11872258 and U19A2098) the Department of Science and Technology of Guangdong Province(No.2019ZT08G315) MOE Laboratory of Deep Earth Science and Engineering(No.DESE202102) 

主　　题：Size effect Inherent anisotropy Fracture toughness Fracture energy Effective FPZ size Quasi-brittle geomaterials 

摘      要：Understanding the size effect exhibited by the fracture mechanism of anisotropic geomaterials is important 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 *** 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 analysis 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.