基于SEM和MIP试验结构性黏土压缩过程中微观孔隙的变化规律

摘要
图/表
参考文献
相关文章 (15)

全文: PDF (625 KB) HTML (1 KB)
输出: BibTeX | EndNote (RIS)

摘要为探求土体在变形过程中微结构形态的演化规律，对湛江结构性黏土进行室内压缩试验，通过真空冷冻升华干燥法对天然土和压缩后土制样，进行扫描电子显微镜扫描试验和压汞试验，基于灰度计算土的三维孔隙率，分析压缩过程中微观孔隙的变化规律。结果表明，较二值化处理获得的二维孔隙率，三维孔隙率物理意义明确，求取方法简单，有较高准确性。湛江天然黏土孔径为1.0～0.1 μm的小孔隙组占优，其孔隙体积占总孔隙体积的73%。压缩过程中，P＞?k前，各孔径组分变化甚微。P＞?k后，随压力的增大，小孔隙含量表现为先增加后降低。各孔隙组对外力的敏感度与孔隙体积含量正相关。由于压汞过程存在“瓶颈”效应，其结果可能会夸大小孔隙的分布密度而低估大孔隙的分布密度。结构性黏土压缩过程中微观结构形态的演化可分为结构微调、结构破损、结构固化3个阶段。该研究有助于深入了解土的变形机制，为结构性土的工程设计提供科学的依据。

	服务

	把本文推荐给朋友
	加入我的书架
	加入引用管理器
	E-mail Alert
	RSS
	作者相关文章

关键词 ：土力学, 结构性黏土, 扫描电子显微镜试验, 压汞试验, 结构屈服压力, 微观孔隙, 孔隙率

Abstract：Compression tests for structured clay in Zhanjiang were conducted to obtain the evolution of soil microstructure in deformation process. Natural soil samples and soil samples after compression tests were prepared for SEM and MIP tests by lyophilization. Three-dimensional porosity was calculated based on gray scale，the evolution of microscopic pores in compression process was qualitatively and quantitatively analyzed. The results show that，compared with two-dimensional porosity based on binary image，the three-dimensional porosity has advantages of explicit physical significance，simple calculation method and high accuracy. Pores with diameters of 1.0–0.1 μm were dominant in natural clay，whose volume took up 73% of total pore volume. When P＜?k，each pore size changed little. When P＞?k，fine pore content firstly increased，subsequently decreased with the increase of the pressure. In the compression process，a positive correlation between the sensitivity of each pore size to external forces and pore volume content was found. The distribution density of the fine pores might be exaggerated while the one of macro-pores might be underestimated in MIP for the bottleneck effect during MIP test. The evolution of microstructure of structured clay in the compression process might be divided into three stages：fine tuning stage，damage stage and solidification stage. The study is helpful for good understanding of deformation mechanism of soil，and provides a scientific basis for engineering design of structured clay.

Key words： soil mechanics structured clay scanning electron microscopy(SEM) test mercury injection test(MIP) structure yield pressure microscopic pore porosity

收稿日期: 2011-07-08

引用本文:

张先伟1，孔令伟1，郭爱国1，拓勇飞2. 基于SEM和MIP试验结构性黏土压缩过程中微观孔隙的变化规律[J]. 岩石力学与工程学报, 2012, 31(2): 406-412.
ZHANG Xianwei1，KONG Lingwei1，GUO Aiguo1，TUO Yongfei2. EVOLUTION OF MICROSCOPIC PORE OF STRUCTURED CLAY IN COMPRESSION PROCESS BASED ON SEM AND MIP TEST. , 2012, 31(2): 406-412.

链接本文:

http://www.rockmech.org/CN/Y2012/V31/I2/406

[1]	李强，鲍苏苏. 基于灰度计算饱和黏土的孔隙率[J]. 重庆师范学院学报：自然科学版，2003，20(1)：30-31.(LI Qiang，BAO Susu. The computation of the porosity of saturated clay based on the gray scale of soft microstructure graph[J]. Journal of Chongqing Normal University：Natural Science，2003，20(1)：30-31.(in Chinese)) " target="_blank">
[3]	房后国，刘娉慧，袁志刚. 海积软土固结过程中微观结构变化特征分析[J]. 水文地质工程地质，2007，34(2)：49-56.(FANG Houguo，LIU Pinghui，YUAN Zhigang. Analysis of characteristics of microstructure change during marine soft soil consolidation[J]. Hydrogeology and Engineering Geology，2007，34(2)：49-56.(in Chinese)) " target="_blank">
[4]	GRIFFITHS F J，JOSHI R C. Changes in pore size distribution due to consolidation of clays[J]. Geotechnique，1989，39(1)：159-167. " target="_blank">
[12]	王宝军，施斌，蔡奕，等. 基于GIS的黏性土SEM图像三维可视化与孔隙度计算[J]. 岩土力学，2008，29(1)：251-255.(WANG Baojun，SHI Bin，CAI Yi，et al. 3D visualization and porosity computation of clay soil SEM image by GIS[J]. Rock and Soil Mechanics，2008，29(1)：251-255.(in Chinese)) " target="_blank">
[9]	KONG L W，LUO H X，TAN L R. Fractal study of pore space distribution of red clay in China[C]// Proceedings of the 10th Asian Regional Conference on Soil Mechanics and Foundation Engineering. Beijing：International Academic Publishers，1995：139-142. " target="_blank">
[2]	张季如，祝杰，黄丽，等. 固结条件下软黏土微观孔隙结构的演化及其分形描述[J]. 水利学报，2008，39(4)：394-400.(ZHANG Jiru，ZHU Jie，HUANG Li，et al. Evolution of micro pore structure of soft clay and its fractal features under consolidation[J]. Journal of Hydraulic Engineering，2008，39(4)：394-400.(in Chinese)) " target="_blank">
[5]	LAPIERRE C，LEROUEIL S，LOCAT J. Mercury intrusion and permeability of Louiseville clay[J]. Canadian Geotechnical Journal，1990，27(6)：761-773. " target="_blank">
[7]	拓勇飞. 湛江软土结构性的力学效应与微观机制研究[硕士学位论文][D]. 武汉：中国科学院武汉岩土力学研究所，2004.(TUO Yongfei. Research on mechanics effect and micromechanism of structural soft clay in Zhanjiang area[M. S. Thesis][D]. Wuhan：Institute of Rock and Soil Mechanics，Chinese Academy of Sciences，2004.(in Chinese)) " target="_blank">
[10]	孔令伟，吕海波，汪稔，等. 湛江海域结构性海洋土的工程特性及其微观机制[J]. 水利学报，2002，(9)：82-88.(KONG Lingwei，LU Haibo，WANG Ren，et al. Engineering properties and micro- mechanism of a structural marine soil in Zhanjiang sea area[J]. Journal of Hydraulic Engineering，2002，(9)：82-88.(in Chinese)) " target="_blank">
[6]	孔令荣，黄宏伟，张冬梅，等. 不同固结压力下饱和软黏土孔隙分布试验研究[J]. 地下空间与工程学报，2007，3(6)：1 036-1 040. (KONG Lingrong，HUANG Hongwei，ZHANG Dongmei，et al. Experiment study of relationship between pore distribution and different stress levels due to consolidation of soft clays[J]. Chinese Journal of Underground Space and Engineering，2007，3(6)：1 036- 1 040.(in Chinese)) " target="_blank">
[8]	南京水利科学院. 土工试验技术手册[M]. 北京：人民交通出版社，2003：70-85.(Nanjing Hydraulic Research Institute. Manual for geotechnical test[M]. Beijing：China Communications Press，2003：70-85.(in Chinese)) " target="_blank">
[11]	唐朝生，施斌，王宝军. 基于SEM土体微观结构研究中的影响因素分析[J]. 岩土工程学报，2008，30(4)：560-565.(TANG Chaosheng，SHI Bin，WANG Baojun. Factors affecting analysis of soil microstructure using SEM[J]. Chinese Journal of Geotechnical Engineering，2008，30(4)：560-565.(in Chinese))