摘要
冻结岩石未冻水和冰含量及损伤特性随温度的变化规律是研究冻结法施工的矿井建设等工程安全稳定的重要问题之一。开展负温下饱水岩石CT扫描实验,获得了0,-2,-5,-10,-20,-30℃下的CT扫描图像。将最大类间方差法与遗传算法相结合,实现了冻结岩石水、冰、岩三相介质的识别及其含量的数字表述。推导出冻结岩石未冻水、冰含量与温度间的理论关系式,并探讨了冰含量和温度梯度对冻结岩石损伤特性的影响规律。结果表明:温度是引起水冰含量及分布状态变化的关键影响因素,岩石的初始损伤和温度的共同作用决定岩石冻结损伤大小。0^-5℃是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阶段。将CT图像三值化处理技术与冻结岩石损伤理论相结合的方法,为冻结岩石水冰含量及宏-细观损伤特性的定量研究提供了新的研究思路。
Unfrozen water and ice content in the frozen rock and its damage characteristic changing with temperature are important to security and stability of freezing-method mining construction engineering. Images of red and gray statured sandstone are obtained in the CT scanning experiments of the water-saturated rock at 0,-2,-5,-10,-20 and-30 ℃. Based on genetic algorithm, the recognition of water, ice, and rock is achieved, and the digital expression of water and ice content are determined. The formulas of relationship between unfrozen water, ice content, and temperature were deduced. The influence law of ice content and temperature gradient on frozen rock damage characteristics was analyzed. The results have shown that temperature is a key factor to influence content of unfrozen water and ice and frozen damage variable. Both initial damage and temperature dominate frozen damage variable. In the temperature range between 0 and-5 ℃, unfrozen water decreases significantly, and frozen damage evolution begins and increases greatly; frozen damage variable keep steady development in temperature range between-5 and-10 ℃; frozen damage tends to be stable after temperature drops to-20 ℃. The method of combining three-valued segmentation of frozen rock CT images and damage theory of rock provides a new thinking for quantitative analysis of damage evolution process of frozen rock and macro-meso damage characteristics.
出处
《采矿与安全工程学报》
EI
CSCD
北大核心
2016年第6期1130-1137,共8页
Journal of Mining & Safety Engineering
基金
国家自然科学基金项目(41272340
41302228)
陕西省科技创新团队项目(2014KCT-30)
中国博士后科学基金面上资助项目(2013M532070)
关键词
冻结岩石
CT图像
三值分割
未冻水
含量
损伤
frozen rock
CT image
three-valued segmentation
unfrozen water
content
damage
