高温和液氮循环作用后花岗岩孔隙结构演化及其劣化机制  

Evolution and damage mechanism of pore structure in granite after high-temperature and liquid nitrogen cycling

作　　者：王振强 狄佳 吴杨 李艳 谷智 高爽 WANG Zhenqiang;DI Jia;WU Yang;LI Yan;GU Zhi;GAO Shuang(China Metallurgical Construction Engineering Group CO.,LTD.,Chongqing 400080,China)

机构地区：[1]中冶建工集团有限公司,重庆400080

出　　处：《科技导报》2024年第24期70-78,共9页Science & Technology Review

基　　金：重庆市社会事业与民生保障科技创新专项(cstc2017shmsA30028);国家资助博士后研究人员计划(GZC20233338);重庆市博士后科学基金项目(CSTB2023NSCQ-BHX0234);重庆市博士后特别资助项目(2023CQBSHTB3024)。

摘　　要：以漳州花岗岩为研究对象,开展了单轴压缩试验和细微观孔隙结构测试,分析了不同特征参数随循环次数变化的演化规律,探究花岗岩在高温和液氮循环作用后的劣化机制。试验结果表明:在高温和液氮循环处理过程中,花岗岩内部小孔隙呈现随机和动态分布,大孔隙呈现广泛分布;随着循环次数增加,花岗岩核磁孔隙度和峰值应变逐渐增大,抗压强度和弹性模量逐渐减小;未经处理的花岗岩破裂模式以单破裂面的剪切或劈裂破坏为主,高温和液氮循环后的花岗岩破裂模式以多破裂面的剪切和劈裂破坏为主;矿物热膨胀系数差异及强度和孔隙结构变化是诱导花岗岩在高温和液氮循环作用下损伤劣化的关键因素。The mechanical properties and pore structure changes caused by the circulation of low-temperature cooling medium in high-temperature granite are of great significance to further understand the high-temperature rock engineering such as dry hot rock development.Taking Zhangzhou granite as the research object,uniaxial compression tests and micro pore structure tests were conducted to analyze the evolution of different characteristic parameters with the number of cycles,and to explore the degradation mechanism of granite after high-temperature and liquid nitrogen cycling.The experimental results showed that during high temperature and liquid nitrogen cycling treatment,the small pores inside the granite exhibited random and dynamic distribution,while the large pores exhibited widespread distribution.As the number of cycles increased,the nuclear magnetic porosity and peak strain of granite gradually increased,while the compressive strength and elastic modulus gradually decreased.The fracture mode of untreated granite was mainly shear or splitting failure with a single fracture surface,while the fracture mode of granite after high temperature and liquid nitrogen cycling was mainly shear and splitting failure with multiple fracture surfaces.The differences in mineral thermal expansion coefficients and changes in strength and pore structure were key factors inducing damage and deterioration of granite under high temperature and liquid nitrogen cycling.

关 键 词：干热岩 温度效应 低场核磁共振 岩石损伤 

分 类 号：TU45[建筑科学—岩土工程]