单轴压缩过程中冻结砂岩的损伤局部化规律研究  

Study on the damage localization law in frozen sandstone during uniaxial compression

作　　者：张慧梅[1,2] 高培雄 贾海梁[1] 王婷 唐丽云[1] ZHANG Huimei;GAO Peixiong;JIA Hailiang;WANG Ting;TANG Liyun(College of Architecture and Civil Engineering,Xi’an University of Science and Technology,Xi’an 710054,China;College of Sciences,Xi’an University of Science and Technology,Xi’an 710054,China;School of Civil Engineering and Architecture,Shaanxi University of Technology,Hanzhong 723001,Shaanxi,China)

机构地区：[1]西安科技大学建筑与土木工程学院,陕西西安710054 [2]西安科技大学理学院,陕西西安710054 [3]陕西理工大学土木工程与建筑学院,陕西汉中723001

出　　处：《冰川冻土》2024年第2期565-577,共13页Journal of Glaciology and Geocryology

基　　金：国家自然科学基金项目(42271148)资助。

摘　　要：损伤局部化是岩石受荷破坏过程中的必经阶段和破坏前兆特征。本文研究冻结岩石受荷破坏过程中的损伤局部化规律,并探讨初始饱和度的影响。在-20℃下对具有不同初始饱和度的冻结砂岩试样进行单轴压缩试验,并采用数字图像相关(DIC)和声发射(AE)系统采集试验过程中的表面变形和声发射信号,分析了试样表面应变局部化模式与内部微裂纹扩展类型。结果表明:(1)初始饱和度令试样的单轴抗压强度产生阶段性变化,并改变了试样各加载阶段占比和破裂过程中的声发射振铃计数分布特征;(2)以40%初始饱和度为转折点,试样的表面应变局部化模式由拉应变为主变为剪应变为主,初始饱和度超过90%时出现了拉、剪应变同时发展的混合模式,并能与试样的最终破坏形态对应;(3)损伤局部化过程中,试样内部的微裂纹扩展类型与表面应变局部化模式基本吻合。最后,结合不同初始饱和度下冻结岩石孔隙中的相组成分变化,分析了其对冻结岩石损伤局部化模式的影响。本研究有助于加深研究人员对冻结岩石力学性质的认识,为寒区岩石工程破坏与失稳预测提供重要参考。In recent years,with the advancement of the western development strategy,China has undertaken extensive rock engineering construction in alpine and cold mountainous areas.During the construction process,inevitable engineering disasters such as slope instability and tunnel collapse have significantly compromised engineering safety.These disasters are usually caused by the gradual accumulation of damage and failure of rock under external load.In addition,low-temperature environmental factors will lead to the change of mechanical properties of rock,and then affect the load-failure process.Damage localization is the necessary stage and precursor of rock failure under load.In this paper,the damage localization of frozen rock under load is studied,and the influence of initial saturation degree is discussed.Uniaxial compression tests of frozen sandstone specimens with different initial saturation degrees were carried out at -20℃.The digital image correlation(DIC)and acoustic emission(AE)systems were used to collect surface deformation and AE signals during the test.Based on the mechanical test results,the mechanical and deformation characteristics of frozen sandstone are analyzed,and the influence of initial saturation degree on the mechanical properties of rock is demonstrated combined with the change of AE count distribution characteristics.Through the analysis of surface deformation,the surface strain localization mode of the specimen is divided into mode I(tensile strain localization),mode Ⅱ(shear strain localization)and mode Ⅲ(mixed localization).The initial saturation degree of 40% is the turning point from mode Ⅰ to mode Ⅱ,and mode Ⅲ appears after the initial saturation degree exceeds 90%.All the modes can correspond to the final failure mode of the specimens.Based on the RA-AF analysis,the types of microcrack propagation in the rock during the strain localization process are shown:type Ⅰ(tensile crack),type Ⅱ(shear crack)and type Ⅲ(mixed crack),which are basically consistent with the surface st

关 键 词：冻结砂岩 初始饱和度 损伤局部化 单轴压缩 应变局部化 微裂纹扩展 

分 类 号：TU752[建筑科学—建筑技术科学] TU45