摘要
为探究寒区砂岩在冻融循环作用下的孔隙结构损伤特性,对经历不同冻融循环次数的红砂岩试样进行了核磁共振试验,并结合多重分形理论,探讨了冻融循环作用对红砂岩不同尺度下孔隙结构的演化规律。结果表明:冻融作用促进了红砂岩孔隙结构发育,未经冻融作用的红砂岩T 2谱曲线呈3峰分布,经历冻融作用的红砂岩T 2谱分布曲线出现了4个峰,反映了冻融过程中红砂岩的孔隙结构演化复杂;单重分形不能表征红砂岩微小孔隙结构特征,但红砂岩微小孔和中大孔均具有良好的多重分形特征;分形参量与孔隙度高度线性相关。微小孔中总体非均质性参数D(0)-D(1)和低概率参数D(-10)-D(0)与孔隙度负相关,赫斯特指数H与孔隙度正相关;中大孔单重分形维数D 2与孔隙度负相关,D(0)-D(1)、D(-10)-D(0)、H均与孔隙度正相关;利用多重分形分析了冻融红砂岩孔隙结构演化规律,为深入研究冻融红砂岩损伤破坏机理提供了理论依据。
In order to explore the pore structure damage characteristics of the sandstone in the cold region under the freeze-thaw cycle,the nuclear magnetic resonance(NMR)test was carried out on the red sandstone samples undergoing different freeze-thaw cycles.Combining the multifractal theory,the evolution law of the pore structure in red sandstone at different scales under freeze-thaw cycles was explored.The results show that the freezing and thawing promotes the development of pore structure of red sandstone.The T 2 spectrum of red sandstone without freeze and thaw shows 3 peaks,and 4 peaks appeared in the T 2 spectrum of freeze-thaw red sandstone.It reflects the complex pore structure evolution of red sandstone during freezing and thawing.Mono-fractal does not characterize the pore structure of red sandstone micro-pores.However,both the micro-pores and medium macro-pores of red sandstone have good multifractal characteristics.Multifractal parameters are highly linearly associated with porosity.In the micro-pores,mono-fractal dimension D 2 is negatively correlated with the porosity,the overall heterogeneity parameters D(0)-D(1)and low probability parameters D(-10)-D(0)negatively correlated with porosity,the Hurst index H is positively correlated with porosity.In the macro-pores,D(0)-D(1),D(-10)-D(0)and H are positively correlated with porosity.The evolution of freeze-thaw red sandstone is analyzed by multi-fractal,it provides a basis for further study of the damage mechanism of freezing-thawing red sandstone.
作者
张慧梅
成瑞
陈世官
郝乐乐
ZHANG Hui-mei;CHENG Rui;CHEN Shi-guan;HAO Le-le(Department of Mechanics,Xi'an University of Science and Technology,Xi'an 710054,China;College of Architecture and Civil Engineering,Xi'an University of Science and Technology,Xi'an 710054,China)
出处
《科学技术与工程》
北大核心
2024年第25期10901-10909,共9页
Science Technology and Engineering
基金
国家自然科学基金(12172280)。
