应力路径试验前后黄土孔隙变化及与力学特性的联系

蒋明镜; 胡海军; 彭建兵; 杨期君

应力路径试验前后黄土孔隙变化及与力学特性的联系 English Version

蒋明镜^1,2,3,
胡海军^1,2,
彭建兵⁴,
杨期君^1,2

1.同济大学地下建筑与工程系，上海 200092；2.同济大学岩土及地下工程教育部重点实验室，上海 200092；3.长安大学公路学院，陕西西安 710064；4. 长安大学西部矿产资源与地质工程教育部重点试验室，陕西西安 710054

基金项目: 国家杰出青年基金项目（51025932）；国家自然科学基金项目（10972158，41130753）；国土资源大调查项目（1212010914013）

详细信息

作者简介:
蒋明镜(1965– )，男，特聘教授，博士生导师，主要从事原状结构性黏土、砂土、非饱和土、太空土、深海能源土的宏、微观试验，本构模型和数值分析方面的研究以及土体逐渐破坏分析。

中图分类号: TU444
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出版历程
- 收稿日期: 2011-10-16
- 发布日期: 2012-08-19

Pore changes of loess before and after stress path tests and their links with mechanical behaviors

(1. Department of Geotechnical Engineering, Tongji University, Shanghai 200092, China; 2. Key Laboratory of Geotechnical and Underground Engineering of Ministry of Education, Tongji University, Shanghai 200092, China; 3. School of Highway, Chang'an University, Xi'an 710064, China; 4. Key Laboratory of Western Mineral Resources and Geological Engineering of Ministry of Education, Chang’an University, Xi'an 710054, China)

摘要

摘要: 应用压汞试验研究了不同应力路径试验前后原状和重塑黄土孔隙分布的变化，探讨了宏观力学特性与孔隙分布的联系。压汞测试结果表明：试验前两种土具有相近孔隙分布的双孔隙结构；两者w＝15%试样等含水率试验后孔隙分布接近，两者饱和试样固结不排水试验后孔隙分布差异较大；应力作用主要对粒间孔隙分布产生影响；常规和减围压三轴等含水率试验后粒间孔隙体积分别减小和增大，相同固结压力下固结不排水减围压三轴试验后粒间孔隙体积比常规三轴试验后的大。原状黄土（w＝15%）在低围压常规三轴试验后未出现剪切带，试样内不同部位孔隙分布未呈较大差异性。根据原状和重塑黄土相同应力路径试验后的孔隙分布差异，探讨了试样宏观力学特性的微观机理，研究结果表明胶结作用、基质吸力和粒间孔隙比对试样的强度和变形起主要作用。
- 黄土 /
- 应力路径 /
- 压汞试验 /
- 孔隙分布 /
- 结构性 /
- 胶结 /
- 基质吸力 /
- 粒间孔隙
Abstract: The pore size distributions (PSDs) of natural loess and remolded loess before and after stress path tests are measured by means of the mercury intrusion porosimetry (MIP) tests, and the relations between PSDs and macro-mechanical behaviours are analyzed. The results from MIP tests indicate that the PSD of remolded loess is similar to that of natural loess before stress path tests, both of which exhibit dual-porosity structure. The PSD of natural loess with w=15% is similar to that of the corresponding remolded loess after the same constant water content triaxial stress path tests, while the PSD of saturated natural loess is different from that of the saturated remolded loess after the same consolidated undrained triaxial stress path tests. The pores influenced by stress are inter-particle pores. The volume of the inter-particle pores after constant water content conventional triaxial compression (CTC) tests and reduced triaxial compression (RTC) tests decreases and increases respectively. The volume of the inter-particle pores after consolidated undrained RTC tests is greater than that after consolidated undrained CTC tests under the same consolidation stress. After the constant water content CTC tests under consolidated stress of 50 kPa which is lower than structural yield stress, the shear plane does not appear in natural loess and the difference of PSDs at different positions of the samples is not great. The macro mechanical characteristics are investigated from the micro point of view according to the difference of PSD between natural loess and remolded loess after the same stress path tests. The research result indicates that cementation bonds, capillary bonds and inter-particle void ratio play important roles in strength and deformation of the samples.
- loess /
- stress path /
- mercury intrusion porosimetry /
- pore size distribution /
- structure /
- cementation /
- matric suction /
- inter-particle pore

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