高压实膨润土孔隙结构特征研究进展

李昆鹏; 陈永贵; 叶为民; 崔玉军

doi:10.11779/CJGE202203001

高压实膨润土孔隙结构特征研究进展 English Version

李昆鹏^{1, 2,},
陈永贵^{1, 2, ,},
叶为民^{1, 2},
崔玉军³

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.
法国国立路桥大学, 法国巴黎 74455

基金项目:

国家自然科学基金项目 42125701

国家自然科学基金项目 41977232

国家自然科学基金项目 41772279

国家自然科学基金项目 42030714

中央高校基本科研业务费项目

详细信息

作者简介:
李昆鹏(1995—)，男，陕西西安人，博士研究生，主要从事环境工程地质及非饱和土力学方面研究。E-mail: kunpeng_lee@tongji.edu.cn

通讯作者:
陈永贵, E-mail: cyg@tongji.edu.cn

中图分类号: TU413
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出版历程
- 收稿日期: 2021-05-10
- 网络出版日期: 2022-09-22
- 刊出日期: 2022-02-28

Advances in studies on pore structure of highly compacted bentonite

LI Kun-peng^{1, 2,},
CHEN Yong-gui^{1, 2, ,},
YE Wei-min^{1, 2},
CUI Yu-jun³

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.
Ecole des PontsParisTech, Paris 74455, France

摘要

摘要: 在详细阐述高压实膨润土孔隙结构组成及其界限孔径确定方法的基础上，全面总结了处置库近场条件下孔隙结构演化规律及其对水力特性影响的研究成果。结果表明：高压实膨润土具有由晶层间孔隙、层叠体间孔隙、集合体间孔隙组成的三孔结构，而描述本构关系时通常简化为由宏观孔隙和微观孔隙构成的双孔结构。双孔结构中宏、微观孔隙界限孔径的确定方法尚未取得共识。孔隙结构演化规律受深地质处置库近场环境影响，包括温度场、渗流场、应力场、化学场，目前对多场耦合作用的研究还不够深入。孔隙比及孔径分布特征无法准确反映膨润土的孔隙结构，尤其体现在孔隙形态及其空间分布规律，应用于讨论孔隙结构对水力特性的影响时存在局限性。基于此，选取适用于描述高压实膨润土本构关系的界限孔径确定方法、揭示热-水-力-化多场耦合作用下孔隙结构演化规律、构建科学合理的孔隙结构量化指标体系并建立相应的水力特性预测模型，是今后需要深入研究的方向。
- 深地质处置库 /
- 高压实膨润土 /
- 孔隙结构 /
- 水力特性 /
- 研究进展
Abstract: Based on the detailed description of pore structure of highly compacted bentonite and approaches used to determine delimiting diameter, the evolution of pore structure under the near-field environment in repository and its influence on hydraulic behavior of the bentonite are summaried. The results show that the pore structure is made up of three classes of pores, including inter-layer, inter-particle and inter-aggregate pores. When describing the constitutive model for bentonite, the pore structure is always simplified as dual pore structure consisting of macro-and micro-pores. The approaches used to determine the delimiting diameter have not reached a consensus. The evolution of pore structure is affected by the near-field conditions of deep geological repository, including temperature, seepage, stress and chemical fields. However, less studies have considered the influences of multi-field coupling on the evolution. The pore ratio and pore-size distribution cannot accurately reflect the actual pore structure, especially the pore shape and spatial distribution. Hence, there are some limitations when the pore ratio and pore-size distribution are used to explore the relationship between the pore structure and the hydraulic behavior of the bentonite. Based on the above, the following aspects should be deeply studied in the future: the optimal approach used to determine the delimiting diameter for describing the constitutive model, the evolution law of pore structure under the coupled T-H-M-C conditions, the scientific and reasonable index system reflecting the actual pore structure, and the prediction model for hydraulic characteristics based on the above index system.
- deep geological repository /
- highly compacted bentonite /
- pore structure /
- hydraulic behavior /
- advances

HTML全文

图 1 深地质处置库近场环境

Figure 1. Typical near-field environment in HLW repository

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图 2 高压实膨润土微观结构组成^[18]

Figure 2. Microstructure of highly compacted bentonite^[18]

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图 3 双孔结构划分示意图

Figure 3. Schematic diagram of dividing dual-pore structure

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图 4 不同温度下高压实膨润土的孔径分布曲线^[22]

Figure 4. Pore-size distribution curves of highly compacted bentonite under various temperatures^[22]

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图 5 湿化过程中孔隙结构演化示意图^[28]

Figure 5. Evolution of pore structure during wetting process^[28]

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图 6 不同吸力下高压实膨润土的ESEM图像^[27]

Figure 6. ESEM photos of highly compacted bentonite at various suctions^[27]

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图 7 干燥及湿化饱和初期高压实膨润土的微观结构示意图^[15]

Figure 7. Micro-structures of highly compacted bentonite in dry state and metting-saturated state^[15]

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图 8 湿化—干燥过程中集合体间孔隙的演化特征^[14]

Figure 8. Evolution of inter-aggregate pore during wetting-drying path^[14]

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图 9 盐溶液对高压实膨润土孔径分布特征的影响^[33]

Figure 9. Effects of salt solution on pore-size distribution of high-pressure bentonite^[33]

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图 10 碱溶液对高压实膨润土孔径分布特征的影响^[37]

Figure 10. Effects of alkali solution on pore-size distribution of high-pressure bentonite^[37]

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图 11 不同孔隙比高压实膨润土的持水曲线^[17]

Figure 11. Water retention curves of highly compacted bentonite with different void ratios^[17]

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图 12 高压实膨润土饱和渗透系数随孔隙比的变化^{[17, 42-46]}

Figure 12. Evolution of saturated permeability of highly compacted bentonite with void ratio^{[17, 42-46]}

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高压实膨润土饱和渗透系数随 ${e_{\text{M}}}$ 及 ${e_{\text{m}}}$ 的变化^[47]

Evolution of saturated permeabilityof highly compacted bentonite with ${e_{\text{M}}}$ and ${e_{\text{m}}}$ ^[47]

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图 14 试样A与试样B的孔径分布曲线^[47]

Figure 14. Pore-size distribution curves of samples A and B^[47]

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图 15 不同尺度高压实膨润土孔隙结构模型^[48]

Figure 15. Model for pore structure of highly compacted bentonite with different scales^[48]

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图 16 高压实膨润土最大膨胀力随孔隙比的变化^{[17, 49-52]}

Figure 16. Evolution of maximum swelling pressure of highly.compacted bentonite with void ratio^{[17, 49-52]}

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表 1 界限孔径确定方法

Table 1 Approaches used to determine delimiting diameter

方法名称	理论基础/假设	文献
PSD法	机械压实只会压缩集合体间孔隙，而对集合体内孔隙几乎无影响	Lloret等^[17]
注汞/退汞法	集合体内孔隙在注汞/退汞过程中仅发生弹性、可逆的变形，集合体间孔隙在退汞时滞留汞液	Delage等^[16]
WRC法	机械压实不会影响集合体内孔隙水的赋存特征	Romero等^[2]
峰值法	将饱和样孔径分布曲线峰值孔径作为界限孔径	Romero等^[20]
谷值法	将压实样孔径分布曲线谷值孔径作为界限孔径	Yuan等^[21]

下载: 导出CSV

表 2 高压实膨润土最大膨胀力与孔隙比的拟合方程

Table 2 Fitting relationships between maximums welling pressure of highly compacted bentonite and void ratio

膨润土类型	拟合方程	R²
GMZ	$\lg {P_{{\text{sf}}}} = 1.995 - 2.395e$	0.949
MX80	$\lg {P_{{\text{sf}}}} = 2.205 - 2.146e$	0.812
Kunigel V1	$\lg {P_{{\text{sf}}}} = 0.969 - 1.461e$	0.926
FEBEX	$\lg {P_{{\text{sf}}}} = 2.562 - 2.585e$	0.905
FoCa	$\lg {P_{{\text{sf}}}} = 3.266 - 4.396e$	0.985

下载: 导出CSV

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