粗、细粒径花岗岩冻融损伤机理及其演化规律  

Degradation mechanism and evolutionary pattern of granites with coarse and fine grains in freezing-thawing condition

作　　者：周科平[1] 张亚民[1] 李杰林[1] 许玉娟[1] 

机构地区：[1]中南大学资源与安全工程学院,长沙410083

出　　处：《北京科技大学学报》2013年第10期1249-1255,共7页Journal of University of Science and Technology Beijing

基　　金：国家自然科学基金资助项目(51074178);高等学校博士学科点专项科研基金资助项目(20090162110036)

摘　　要：通过粗、细两种颗粒花岗岩的冻融循环试验和岩石力学试验,研究了不同粒径岩石的冻融循环作用对岩石物理力学特性的影响.利用核磁共振技术对冻融循环前后的岩样进行检测,得到了横向弛豫时间谱的变化和岩样核磁共振成像,分析了岩样在冻融前后的孔隙度变化、空隙结构及分布的演化特性等.采用宏观唯象损伤理论和自洽理论对不同粒径花岗岩在冻融条件下的宏、细观损伤演化规律进行了分析.研究发现在冻融循环作用下,岩石内部的孔隙逐渐增多,不断造成岩石的强度损失;损伤模型的计算值与实际相符,但不同损伤理论对花岗岩损伤程度趋势变化的反应存在差异;细颗粒花岗岩呈现出较高冻融耐久性.The influence of freezing and thawing cycles on the physical and mechanical properties of granites with coarse and fine grains was studied by freezing and thawing cycle experiment and rock mechanic test. Rock samples were detected by nuclear magnetic resonance （NMR）, their transverse relaxation time spectra and NMR images were got before and after freezing and thawing cycle experiment, and the porosity variation, pore structure and evolution laws were discussed. The macro phenomenological theory and the self-consistency theory were used to analyze the degradation principle of rock samples in macro and micro scales, respectively. It is found that the number of pores increases in the action of freezing and thawing cycles, which weakens the strength of rock samples. The theoretical values of damage models are in consistence with experimental data, but different damage theories show different results about the development of damage tendency. Granite with fine grains shows a better durability in the action of freezing and thawing cycles.

关 键 词：花岗岩 冷冻 融化 劣化 核磁共振 

分 类 号：P588.12[天文地球—岩石学] TU458.2[天文地球—地质学]