(1. School of Resources and Safety Engineering,Central South University,Changsha,Hunan 410083,China;
2. Shanghai Niumag Electronic Technology Co.,Ltd.,Shanghai 200062,China)
Abstract:For knowing the variation characteristic of rock microstructure under freezing and thawing cycles,the experimental study on granite sample is conducted under different freezing and thawing cycles of 0 time,10,20,30 and 40 times with the freezing temperature of -40 ℃ and thawing temperature of 20 ℃. The nuclear magnetic resonance(NMR) is used to test the samples after freezing and thawing cycles;and the crosswise relaxation time T2 distribution and NMR imaging are obtained. The results show that:T2 distribution of granite exhibits three peaks and the subtotal spectrum area between the first peak and second peak occupies more than 98% of the total area,which means the micro pores are in the majority. After different freezing-thawing cycles of 10,20,30 and 40 times,the T2 spectrum area has changed obviously;and the porosity has increased by 14%,0.9%,16.2% and 1.6% respectively. Also,the space distributions of pores have been visually shown by the NMR imaging. The variation law of NMR characteristics in rock under freezing-thawing cycles has provided the reliable experimental results for the research works of rock damage mechanism under freezing and thawing cycles.
周科平1,李杰林1,许玉娟1,张亚民1,杨培强2,陈路平2. 冻融循环条件下岩石核磁共振特性的试验研究[J]. 岩石力学与工程学报, 2012, 31(4): 731-737.
ZHOU Keping1,LI Jielin1,XU Yujuan1,ZHANG Yaming1,YANG Peiqiang2,CHEN Luping2. EXPERIMENTAL STUDY OF NMR CHARACTERISTICS IN ROCK UNDER FREEZING AND THAWING CYCLES. , 2012, 31(4): 731-737.
NICHOLSON D T,NICHOLSON F H. Physical deterioration of sedimentary rocks subjected to experimental freeze-thaw weathering[J]. Earth Surface Processes and Landforms,2000,25(12):1 295-1 307.
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