岩土力学 ›› 2019, Vol. 40 ›› Issue (9): 3524-3532.doi: 10.16285/j.rsm.2018.1066

• 基础理论与实验研究 • 上一篇    下一篇

冻融作用下砂岩孔隙结构损伤特征研究

李杰林1, 2,朱龙胤1, 2,周科平1, 2,刘汉文1, 2,曹善鹏1, 2   

  1. 1. 中南大学 资源与安全工程学院,湖南 长沙 410083;2. 中南大学 高海拔寒区采矿工程技术研究中心,湖南 长沙 410083
  • 收稿日期:2018-06-19 出版日期:2019-09-10 发布日期:2019-09-05
  • 通讯作者: 周科平,男,1964年生,博士,教授,博士生导师,主要从事深部采矿与矿山岩石力学方面的教学与研究工作。E-mail: kpzhou@vip.163.com E-mail:lijielin@163.com
  • 作者简介:李杰林,男,1982年生,博士,副教授,主要从事采矿工程与寒区岩石力学方面的研究工作
  • 基金资助:
    国家自然科学基金项目(No.41502327,No.51474252,No.51774323);国家重大科学仪器设备开发专项(No.2013YQ17046310);中南大学中央高校基本科研业务费专项资金项目(No.2017zzts795,No.2019zzts165)

Damage characteristics of sandstone pore structure under freeze-thaw cycles

LI Jie-lin1, 2, ZHU Long-yin1, 2, ZHOU Ke-ping1, 2, LIU Han-wen1, 2, CAO Shan-peng1, 2   

  1. 1. School of Resources and Safety Engineering, Central South University, Changsha, Hunan 410083, China; 2. Research Center for Mining Engineering and Technology in Cold Regions, Central South University, Changsha, Hunan 410083, China
  • Received:2018-06-19 Online:2019-09-10 Published:2019-09-05
  • Supported by:
    This work was supported by the National Natural Science Foundation of China(41502327, 51474252, 51774323), the National Major Scientific Instruments and Equipment Development Projects (2013YQ17046310) and the Fundamental Research Funds for the Central Universities of Central South University (2017zzts795, 2019zzts165).

摘要: 为研究冻融作用下砂岩孔隙结构损伤特征,选取5个岩样进行100次冻融循环试验,并采用核磁共振技术对砂岩孔隙结构进行测试,得到了冻融作用下砂岩的核磁共振弛豫时间T2谱分布、孔隙度等细观结构特征。根据孔隙的孔径分布特征,按孔径尺寸划分为小孔隙、中孔隙、大孔隙3类,并采用扩散双电层理论对不同尺寸孔隙水分布规律进行了分析。结果表明:随着冻融循环次数增加,核磁共振T2分布右移,砂岩的孔隙度增大;同时,水?岩作用导致部分矿物质溶解在孔隙水中,使得孔隙水中离子浓度升高,导致岩石内部产生大量的次生孔隙。随着孔径尺寸的增加,孔隙中的束缚水含量逐渐减少,且小孔隙的束缚水含量远远大于大孔隙;在低温冻结时,自由水先于束缚水结冰,小孔隙束缚水离子浓度的增长幅度小于大孔隙,进而产生了离子浓度差,使得小孔隙中的水分子向大孔隙迁移,造成小孔隙的损伤速率远小于大孔隙。因此,小孔隙在水?岩作用与冻胀压力的作用下不断发育,大孔隙则在冻胀压力下快速扩张、发育,直至岩样发生宏观破坏。

关键词: 冻融循环, 核磁共振, 孔隙结构, 损伤特性

Abstract: To study the damage characteristics of sandstone pore structure under freeze-thaw cycles, five rock specimens were selected to conduct 100 freeze-thaw cycles, and the pore structure of sandstone was measured by nuclear magnetic resonance technology (NMR). The mesostructure characteristics such as T2 spectrum distribution and sandstone porosity were obtained under the freeze-thaw effect. According to the distribution of pores, the pore size was divided into three categories: mini-pores, meso-pores, and macro-pores. Meanwhile, the diffusion electric double layer theory was used to analyze the distribution of pore water with different pore sizes. The results show that as the number of freeze-thaw cycles increases, the T2 distribution of NMR shifts to the right and the porosity of the sandstone increases. At the same time, some minerals are dissolved in the pore water under the water-rock effect, which causes the ion concentration to increase in the pore water and results in a large number of secondary pores within the rock. With the increase of pore size, the bound water content in the pores gradually decreases, and the bound water content of small pores is much larger than that of macro-pores. At a low temperature, the free water freezes before the bound water, and the increase of ion concentration of bound water in small pore is lower than that of macro-pores, which leads to a difference in ion concentration. As a result, the water molecules in the small pores migrate to the macro-pores and the damage rate of small pores is much smaller than that of macro-pores. Therefore, the mini-pores continuously deteriorate under the effect of water-rock interaction and the frost heaving pressure; the macro-pores are rapidly developed and expanded under the frost heaving until the macroscopic damage of the rock samples.

Key words: freeze-thaw cycles, nuclear magnetic resonance(NMR), pore structure, damage characteristics

中图分类号: 

  • TU411
[1] 杨赫, 程卫民, 刘震, 王文玉, 赵大伟, 王文迪. 注水煤体有效渗流通道结构分形特征 核磁共振试验研究[J]. 岩土力学, 2020, 41(4): 1279-1286.
[2] 孙静, 公茂盛, 熊宏强, 甘霖睿, . 冻融循环对粉砂土动力特性影响的试验研究[J]. 岩土力学, 2020, 41(3): 747-754.
[3] 孟祥传, 周家作, 韦昌富, 张坤, 沈正艳, 杨周洁, . 盐分对土的冻结温度及未冻水含量的影响研究[J]. 岩土力学, 2020, 41(3): 952-960.
[4] 高峰, 曹善鹏, 熊信, 周科平, 朱龙胤, . 冻融循环作用下受荷青砂岩的脆性演化特征[J]. 岩土力学, 2020, 41(2): 445-452.
[5] 张峰瑞, 姜谙男, 杨秀荣, 申发义. 冻融循环下花岗岩剪切蠕变试验与模型研究[J]. 岩土力学, 2020, 41(2): 509-519.
[6] 彭家奕, 张家发, 沈振中, 叶加兵, . 颗粒形状对粗粒土孔隙特征和渗透性的影响[J]. 岩土力学, 2020, 41(2): 592-600.
[7] 丑亚玲, 黄守洋, 孙丽源, 王莉杰, 岳国栋, 曹伟, 盛煜, . 基于冻融作用的氯盐渍土−钢块界面力学模型[J]. 岩土力学, 2019, 40(S1): 41-52.
[8] 李玲, 刘金泉, 刘造保, 刘桃根, 王伟, 邵建富, . 砂-黏土混合物高压压实性能试验研究[J]. 岩土力学, 2019, 40(9): 3502-3514.
[9] 王震, 朱珍德, 陈会官, 朱姝, . 冻融作用下岩石力-热-水耦合本构模型研究[J]. 岩土力学, 2019, 40(7): 2608-2616.
[10] 刘语, 张巍, 梁小龙, 许林, 唐心煜. 南京粉细砂空间孔隙结构表征单元体确定[J]. 岩土力学, 2019, 40(7): 2723-2729.
[11] 王士权, 魏明俐, 何星星, 张亭亭, 薛 强, . 基于核磁共振技术的淤泥固化水分转化机制研究[J]. 岩土力学, 2019, 40(5): 1778-1786.
[12] 高 峰, 熊 信, 周科平, 李杰林, 史文超, . 冻融循环作用下饱水砂岩的强度劣化模型[J]. 岩土力学, 2019, 40(3): 926-932.
[13] 任克彬, 王 博, 李新明, 尹 松, . 毛细水干湿循环作用下土遗址的强度特性 与孔隙分布特征[J]. 岩土力学, 2019, 40(3): 962-970.
[14] 胡田飞, 刘建坤, 王天亮, 岳祖润, . 粉质黏土变形特性的冻融循环效应及其双屈 服面本构模型[J]. 岩土力学, 2019, 40(3): 987-997.
[15] 江强强, 刘路路, 焦玉勇, 王 浩, . 干湿循环下滑带土强度特性与微观结构试验研究[J]. 岩土力学, 2019, 40(3): 1005-1012.
Viewed
Full text


Abstract

Cited

  Shared   
  Discussed   
No Suggested Reading articles found!