高温养护及不同冷击方式下混凝土宏细观损伤规律研究  

Study on Macro-microscopic Damage Characteristics of Concrete Under High-temperature Curing and Different Cold Strike Methods

作　　者：宿辉[1,2] 王新宇 赵永春 刘绍兴 袁乐忠 柴宏利 张婷[3] 韩小庆[4] SU Hui;WANG Xin-yu;ZHAO Yong-chun;LIU Shao-xing;YUAN Le-zhong;CHAI Hong-li;ZHANG Ting;HAN Xiao-qing(School of Water Conservancy and Hydroelectric Power,Hebei University of Engineering,Handan 056038,China;Key Laboratory of Intelligent Water Resources of Hebei Province,Hebei University of Engineering,Handan 056038,China;China Institute of Water Resources and Hydropower Research,Beijing 100038,China;Jizhong Energy Fengfeng Group Co.,Ltd.,Handan 056200,China)

机构地区：[1]河北工程大学水利水电学院,河北邯郸056038 [2]河北工程大学河北省智慧水利重点实验室,河北邯郸056038 [3]中国水利水电科学研究院,北京100038 [4]冀中能源峰峰集团有限公司,湖北邯郸056200

出　　处：《水电能源科学》2024年第11期95-98,91,共5页Water Resources and Power

基　　金：河北省重大科技专项(E2020402087);河北省高等学校科学技术研究项目(QN2021030);河北省水利科技计划项目(2018-41);河北省自然科学基金项目(E2021402023)。

摘　　要：高地温引水隧洞通水后围岩温度场会产生急剧变化,会使混凝土衬砌结构遭受热—冷冲击作用而产生损伤。为揭示混凝土衬砌宏细观损伤规律,开展高温养护及不同冷击方式下混凝土的单轴压缩试验、核磁共振扫描试验(NMR)和SEM扫描试验,分析高温养护后不同冷击方式对混凝土抗压强度、孔结构及细观形貌特征的影响,探究不同冷击方式下高温混凝土宏细观损伤规律。结果表明,随着初始养护温度增加,混凝土的单轴抗压强度先增加后减小,60℃养护后混凝土宏观力学强度达到最大;随着初始养护温度增加,混凝土孔隙率不断增大。骤降冷击方式对混凝土孔隙率、大孔隙占比和小孔隙占比等孔隙结构特征具有明显影响;相对自然冷击,骤降冷击下混凝土水泥砂浆界面产生较为明显的温度裂缝,混凝土损伤更为显著。研究成果可为我国西部高地温环境下引水隧洞安全施工与运营提供参考。The introduction of water into a tunnel at elevated temperatures results in significant variations in the sur-rounding rock temperature,leading to thermal-cold shock on concrete lining structures.To elucidate the macroscopic and microscopic damage mechanisms of concrete linings,a comprehensive study was conducted.Uniaxial compression tests,nuclear magnetic resonance(NMR)scans,and scanning electron microscopy(SEM)examinations were performed on concrete specimens subjected to high-temperature curing and different cold strike methods.The effects of various cooling approaches on compressive strength,pore structure,and microscopic characteristics of concrete were analyzed to investi-gate the damage mechanisms under different cold strike methods.The results indicate that with an increase in initial cu-ring temperature,the uniaxial compressive strength of concrete initially rises and then decreases,reaching a maximum af-ter curing at 60℃.Concurrently,an increase in the initial curing temperature leads to a continuous rise in concrete poros-ity.The rapid cold strike significantly influences pore characteristics,including total porosity,the proportion of large and small pores,etc.Compared to natural cold strike,rapid cold strike induces noticeable temperature-induced cracks at the cement-sand mortar interface,emphasizing the manifestation of concrete damage.The findings of this study can provide theoretical insights for the safe construction and operation of water diversion tunnels in high-elevation warm environments in western China.

关 键 词：高地温 混凝土衬砌 冷击方式 孔结构 损伤演化 

分 类 号：TV331[水利工程—水工结构工程]