Thermal effects on prediction accuracy of dense granite mechanical behaviors using modified maximum tangential stress criterion

作     者：Gan Feng Chun Zhu Xiaochuan Wang Shibin Tang Gan Feng;Chun Zhu;Xiaochuan Wang;Shibin Tang

作者机构：College of Water Resource and HydropowerSichuan UniversityChengdu610065China Key Laboratory of Deep Earth Science and Engineering(Sichuan University)Ministry of EducationChengdu610065China Hubei Key Laboratory of Waterjet Theory and New TechnologyWuhan UniversityWuhan430072China School of Earth Sciences and EngineeringHohai UniversityNanjing210098China State Key Laboratory of Coastal and Offshore EngineeringDalian University of TechnologyDalian116024China 

出 版 物：《Journal of Rock Mechanics and Geotechnical Engineering》 (岩石力学与岩土工程学报（英文版）)

年 卷 期：2023年第15卷第7期

页      面：1734-1748页

核心收录：

学科分类：08[工学] 080104[工学-工程力学] 0818[工学-地质资源与地质工程] 0801[工学-力学（可授工学、理学学位）] 

基　　金：supported by the open fund of the Key Laboratory of Deep Earth Science and Engineering(Sichuan University),the Ministry of Education(Grant No.DESEYU202206) the Young Elite Scientists Sponsorship Program by CAST of China(Grant No.2021QNRC001) the Natural Science Foundation of Sichuan Province,China(Grant No.52104143),which are greatly appreciated。 

主　　题：Underground geotechnical engineering Hot dry rock(HDR) Geothermal temperature Fracture behavior 

摘      要：Thermally-induced changes in the fracture properties of geological reservoir rocks can influence their stability,transport characteristics,and performance related to various deep subsurface energy projects.The modified maximum tangential stress(MMTS)criterion is a classical theory for predicting the fracture instability of rocks.However,there is a lack of research on the accuracy of MMTS theory when rocks are subjected to different temperatures.In this study,mechanical theoretical analysis and failure and fracture mechanics experiments of granite under the influence of temperatures ranging from 20℃to 600℃are carried out.The results showed that the theoretical estimated value of MMTS differs significantly from the experimental data at 20℃-600℃.The Keff/KIC ratio is less than the experimental test value due to the critical crack growth radius(rc)estimated by the conventional method being larger than the critical crack growth radius(rce)derived from the experimental data.Varied temperatures affect the fracture process zone size of fine-grained,compact granite,and the MMTS theoretical estimation results.Therefore,it is essential to modify the critical crack growth radius for MMTS theory to accurately predict the fracture characteristics of thermally damaged rocks.In addition,the variation of the rock’s me-chanical properties with temperature and its causes are obtained.Between 20℃and 600℃,the mode-Ⅰ,mode-Ⅱ,and mixed-mode(a-30℃and 45℃)fracture toughness and Brazilian splitting strength of the granite decrease by 80%and 73%,respectively.When the rock is heated above 400℃,its deterioration is mainly caused by a widening of its original cracks.