高温后花岗岩微观结构演化特性与动态力学性能研究  

Micro-structure characteristics and dynamic mechanical properties of granite after high temperature

作　　者：李艳[1] 程禹翰 翟越[1] 魏盛宇 杨宇冰 赵瑞峰 梁文彪 LI Yan;CHENG Yu-han;ZHAI Yue;WEI Sheng-yu;YANGYu-bing;ZHAO Rui-feng;LIANG Wen-biao(School of Geological Engineering and Geomatics,Chang'an University,Xi'an,Shaanxi 710061,China;School of Sciences,Chang'an University,Xi'an,Shaanxi 710061,China)

机构地区：[1]长安大学地质工程与测绘学院,陕西西安710061 [2]长安大学理学院,陕西西安710061

出　　处：《岩土力学》2022年第12期3316-3326,共11页Rock and Soil Mechanics

基　　金：陕西省自然科学基础研究项目(No.2020JQ-373);中央高校基本科研业务费(No.300102122108)。

摘　　要：为研究高温后花岗岩矿物成分变化规律、微观结构演化特性及其与动态力学性能之间的关系,以甘肃省北山花岗岩为研究对象开展了20~1 000℃的高温试验,借助切片技术和偏光显微镜得到了高温后花岗岩的微观图像。通过矿物成分分析、微裂隙特征识别及参数计算,研究高温后花岗岩矿物成分、矿物含量、微观结构特征参数随温度的演化过程。利用霍普金森压杆系统对高温后花岗岩开展动态冲击压缩试验,分析温度、加载速率和微观结构特征对动态峰值应力的影响,并建立微观结构特征与宏观动态力学性能之间的定量关系。结果表明:高温作用对花岗岩的矿物成分、微观结构和冲击压缩强度具有显著影响,600℃为阈值温度;加载速率对冲击压缩强度也具有显著影响,且加载速率越大,温度对宏观动态力学性能的影响越小;高温后花岗岩的微观结构随温度的演化过程是其宏观动态力学性能随温度变化的内在机制,微观裂隙特征与动态峰值应力具有显著相关性,且裂隙平均宽度是影响花岗岩动态峰值应力的主要因素。In order to study the changes of mineral composition, micro-structure evolution characteristics and their relationship with dynamic mechanical properties of granite after high temperature, 20-1 000 ℃ high temperature tests were carried out based on the Beishan granite from Gansu Province. Microscopic images of granite after high temperature treatment were obtained by means of slicing technique and polarizing microscope. The evolution of mineral composition, mineral content and micro-structure characteristic parameters of granite with temperature were studied through mineral composition analysis, micro-cracks characteristic identification and parameters calculation. Subsequently, dynamic impact compression tests of high temperature treated granite were carried out by split Hopkinson pressure bar(SHPB) system, to analyze the effects of temperature, impact rate and micro-structure characteristics on dynamic peak stress. On this basis, the quantitative relationship between micro-structure characteristics and macroscopic dynamic mechanical properties was established. The results show that high temperature has a significant effect on the mineral composition, micro-structure and impact compression peak stress of granite, and 600 ℃ is taken as the threshold temperature.The impact rate also significantly affects the impact compressive strength, and the higher the impact rate, the less the influence of temperature on the macroscopic dynamic mechanical properties. The evolution of the micro-structure of granite after high temperature is the internal mechanism of the changes of its macroscopic dynamic mechanical properties with temperature. The characteristics of micro-cracks are significantly correlated with the dynamic peak stress, and the average width of cracks is the main factor affecting the dynamic peak stress of granite.

关 键 词：高温作用 花岗岩 微观结构特征 动态力学性能 相关性分析 

分 类 号：TU452[建筑科学—岩土工程]