基于CT图像的冻结岩石冰含量及损伤特性分析  

Analysis of Ice Content and Damage Characteristics of Frozen Rock Based on Pseudo-color Enhanced CT Image

作　　者：刘慧[1] 杨更社[1] 叶万军[1] 申艳军[1] 唐丽云[1] 

机构地区：[1]西安科技大学建筑与土木工程学院,西安710054

出　　处：《地下空间与工程学报》2016年第4期912-919,共8页Chinese Journal of Underground Space and Engineering

基　　金：国家自然科学基金(41272340;41172262;41302228;41502298;11402195);陕西省科技创新团队(2014KCT-30);中国博士后科学基金面上资助项目(2013M532070)

摘　　要：冻结岩石中冰含量对其热力学及损伤特性有重要影响,研究岩石冻结过程中冰含量随温度的变化规律可以为冻结岩石工程的安全稳定性评价提供科学依据。运用CT识别技术,进行不同温度梯度下冻结岩石的CT扫描实验,获得20℃、-2℃、-5℃、-10℃、-20℃、-30℃下岩石的CT扫描图像,实现了冻结岩石CT图像的伪彩色增强和直方图分析,完成了冻结岩石冰含量及损伤信息的数字表述,对冰含量随温度的变化规律进行定量分析。依据损伤力学理论,定义以冰含量表示的冻结损伤变量,探讨了未冻水含量和温度梯度对冻结岩石损伤特性的影响规律。研究结果表明:(-2℃,-5℃)是水冰剧烈相变的温度区间,冻结损伤演化起始和急剧增大阶段;(-5℃,-10℃)是冻结损伤发展阶段;(-20℃,-30℃)是冻结损伤趋于稳定的温度区间。所定义的冻结损伤变量能够描述温度降低过程中岩石损伤的演化过程,基于冻结岩石CT图像伪彩色增强的冻结岩石损伤演化的定量分析为冻结岩石工程的稳定性研究提供了新的思路和方法。Ice content has great influence on thermodynamic and damage properties of frozen rock. Study on variation law of ice content with temperature in the process of freezing can provide scientific basis for the stability analysis in frozen rock engineering. By CT identification technology,CT scanning experiment of frozen rock was carried out under different thermal gradients as 20 ℃,-2 ℃,-5 ℃,-10 ℃,-20 ℃ and-30 ℃. The CT scanning images of frozen rock at various temperatures were obtained. Based on digital image processing theory and method,according to meso-scopic physical information contained in CT images of frozen rock,the CT images of frozen rock under different thermal gradients were analyzed. Pseudo-color enhancement method was applied and histogram analysis of frozen rock CT images was obtained,the digital representation of ice content and damage information for frozen rock was realized.By the method proposed in this paper the variation of ice content with temperature was analyzed quantitatively. According to damage mechanics theory,damage variable expressed by ice content was defined,the influence law of unfrozen water content and thermal gradient on damage properties of frozen rock was discussed. The results show that the strenuous phase change from water to ice occurred in（-2 ℃ to- 5 ℃）,frozen damage evolution beginning and increasing greatly in range of（-2 ℃ to-5 ℃）,frozen damage steady development in temperature range of（- 2 ℃ to-5 ℃）,frozen damage tends to be stable after temperature drops to-20 ℃.The pseudo-color enhancement technology of frozen rock provides a new method for quantitative analyzing damage evolution process of frozen rock under different low thermal gradients.

关 键 词：冻结岩石 CT图像 伪彩色增强 冰含量 损伤 温度梯度 

分 类 号：TU45[建筑科学—岩土工程]