缓冲/回填材料——膨润土颗粒及其混合物研究进展

刘樟荣; 崔玉军; 叶为民; 王琼; 张召; 陈永贵

doi:10.11779/CJGE202008004

缓冲/回填材料——膨润土颗粒及其混合物研究进展 English Version

刘樟荣^1,,
崔玉军^{1, 3},
叶为民^{1, 2, ,},
王琼^{1, 4},
张召¹,
陈永贵^{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.
法国国立路桥大学,法国　巴黎　77455
4.
同济大学高等研究院,上海　200092

基金项目:

国家重大科研仪器研制项目 41527801

国家自然科学基金项目 41672271

国家自然科学基金项目 41807237

上海市浦江人才计划项目 18PJ1410200

详细信息

作者简介:
刘樟荣(1990—),男,江西赣州人,博士,博士后,主要从事非饱和土力学与工程地质方面的研究工作。E-mail：liuzr@tongji.edu.cn

通讯作者:
叶为民, E-mail：ye_tju@tongji.edu.cn

中图分类号: TU41
计量
- 文章访问数: 488
- HTML全文浏览量: 61
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出版历程
- 收稿日期: 2019-09-15
- 网络出版日期: 2022-12-05
- 刊出日期: 2020-07-31

Advances in researches on buffer/backfilling materials—bentonite pellets and pellet mixtures

LIU Zhang-rong^1,,
CUI Yu-jun^{1, 3},
YE Wei-min^{1, 2, ,},
WANG Qiong^{1, 4},
ZHANG Zhao¹,
CHEN Yong-gui^{1, 2}

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.
Laboratoire Navier, Ecole des Ponts ParisTech, Paris 77455, France
4.
Institute for Advanced Study, Tongji University, Shanghai 200092, China

摘要

摘要: 膨润土颗粒是一种用于填充高放废物地质处置库中各种施工接缝和空隙的缓冲/回填材料。从膨润土颗粒的制备方法、填充技术与堆积性质、热传导特性、水力特性、结构演化规律及力学特性等6个方面,全面回顾和总结了近年来对膨润土颗粒的研究成果与最新进展,并分别指出了各方面值得进一步深入研究的几个课题。研究表明,膨润土颗粒可由多种方法制备,也可采用多种技术填充到处置库中,其堆积干密度和均匀性与充填技术、级配、堆积方式等因素有关,其热传导系数与干密度、含水率和温度等因素有关,其水力–力学特性与级配、干密度及温度等因素有关。通水水化或降低吸力过程中,颗粒混合物由初始松散结构逐渐转变为胶结融合结构,及至水化饱和后基本达到宏观上的均一化结构,但微观层次的均一化过程仍将持续漫长的时间。考虑到处置库实际运营工况的复杂性,科学高效的颗粒混合物填充技术、多场（热–水–化–力）耦合条件下的颗粒混合物水力–力学特性及结构演化规律是今后值得深入探索的研究方向。
- 深地质处置 /
- 缓冲/回填材料 /
- 膨润土颗粒 /
- 颗粒混合物
Abstract: The bentonite pellet is considered as an alternative buffer/backfilling material to fill technological voids and empty space in high-level radioactive waste (HLW) repository. The previous studies on the bentonite pellets are carefully reviewed and summarized, including their manufacturing methods, emplacement techniques, thermal conductivity, hydraulic behavior, structural change and mechanical behavior. Correspondingly, the research subjects worth further investigation are put forward. The results in the literatures indicate that the pellets can be manufactured and emplaced using several techniques, which together with size gradation and packing protocol can influence the packing dry density and homogeneity. For the pellet mixtures, the thermal conductivity is mainly governed by dry density, water content and temperature, and the hydro-mechanical behavior is related to size gradation, dry density and temperature. Upon liquid or suction controlled hydration, the initial loose-structured pellet mixtures will gradually transfer to the cemented state and finally present a homogeneous appearance at saturation. However, much longer duration is required before getting a completely homogeneous state. Considering the complexity of the operation conditions in a HLW repository, the improvements on emplacement techniques of the pellets and the investigations on the hydro-mechanical behavior and structural change under the coupled thermo-hydro-chemo-mechanical conditions should be further conducted.
- geological disposal /
- buffer/backfilling material /
- bentonite pellet /
- pellet mixture

HTML全文

图 1 膨润土颗粒在高放废物处置库中的应用

Figure 1. The application of bentonite pellets in HLW repository

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图 2 挤压法及其制备的颗粒^[7-8]

Figure 2. Extrusion method and produced pellets^[7-8]

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图 3 辊压法及其制备的颗粒^[7,11]

Figure 3. Roller compaction method and produced pellets^[7,11]

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图 4 压实法与压实–破碎法制备的颗粒^[12-13]

Figure 4. Pellets manufactured by compaction and compaction-crushing methods^[12-13]

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图 5 带式输送法、螺旋输送法和气动喷射法示意图

Figure 5. Schematic diagrams of pellets emplaced by belt, auger and pneumatic conveying

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图 6 矩形槽和环形槽填充试验^[26-27]

Figure 6. Pellet filling tests in rectangle and annular gaps^[26-27]

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图 7 颗粒混合物的热传导系数测试技术^[8,28]

Figure 7. Measuring techniques of thermal conductivity for pellet mixtures^[8,28]

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图 8 热传导系数随干密度的变化^[11,25]

Figure 8. Evolution of thermal conductivity with dry density^[11,25]

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图 9 不同干密度FEBEX膨润土颗粒混合物的持水曲线^[10]

Figure 9. Curves of water retention of FEBEX bentonite pellets with different dry densities^[10]

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图 10 FEBEX膨润土颗粒混合物渗透系数随时间的演化^[10]

Figure 10. Evolution of hydraulic conductivity with time for FEBEX bentonite pellets^[10]

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图 11 不同吸力下单个颗粒的结构特征^[31]

Figure 11. Structural characteristics of single pellet at different suctions^[31]

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图 12 水化过程中颗粒混合物的结构演化^[39-40]

Figure 12. Structural evolution of pellet mixtures during hydration^[39-40]

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图 13 颗粒强度和耐磨性试验设备^[8]

Figure 13. Devices used in pellet strength and abrasion tests^[8]

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图 14 不同条件下颗粒混合物的膨胀力时程曲线^[9,42]

Figure 14. Evolution of swelling pressure with time for pellet mixtures under different conditions^[9,42]

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图 15 膨胀变形与竖向荷载及吸力的关系^[10]

Figure 15. Evolution of swelling strain with vertical stress and suction^[10]

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图 16 弹、塑性压缩系数随吸力的变化^[10]

Figure 16. Evolution of elastoplastic compressibility coefficients ( $κ$ $κ$ and $λ$ $λ$ ) with suction^[10]

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表 1 膨润土颗粒的制备方法比较

Table 1 Overview of manufacture techniques for bentonite pellets

方法	原理	颗粒性质	优点	缺点
挤压法	机械压实	形状规则大小统一	工序简单,效率高,机械化程度高	需要特定的制样模具,粒径范围有限
辊压法
压实法
压实–破碎法	机械压实机械破碎	形状各异大小不一	可制备各种粒径的颗粒	工序多,效率低,难以控制机械破碎的初始粒径
湿–干–破碎法	吸力固结机械破碎	形状各异大小不一	可制备各种粒径的颗粒	工序多,效率低,难以控制机械破碎的初始粒径

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表 2 膨润土颗粒的填充方法比较

Table 2 Overview of filling techniques for bentonite pellets

方法	主要优点	主要缺点	适用性
带式输送	效率高	粉尘多易离析设备笨重	填充较大的空隙或回填巷道
螺旋输送	效率较高粉尘较少均匀性较好	设备较笨重	填充较大的接缝、空隙或回填巷道
气动喷射	效率较高堆积密度大	粉尘多均匀性差	可填充各种接缝、空隙或回填巷道
人工填充	适应性强	粉尘多效率低	可填充各种接缝、空隙或回填巷道

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