多边界条件下缓冲/回填材料的膨胀特性
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摘要
高放废物处置库中缓冲/回填材料的膨胀特性是评价其屏障性能的关键因素。受试验仪器等条件的限制,以往的膨胀试验基本都是在恒体积和恒应力这两种极端边界条件下开展的,无法有效反映处置库中的复杂应力–应变环境。研发了一套新型的多边界条件膨胀仪,集成了恒体积、恒应力和柔性等刚度3种边界条件。利用该膨胀仪对中国高庙子(GMZ)缓冲/回填材料开展了一系列膨胀试验,分析了边界条件对试样膨胀特性的影响。结果表明:研发的多边界条件膨胀仪具有操作简单、性能稳定等特点,能有效地模拟各种边界条件;边界条件对试样膨胀指标具有重要影响,对应的最终膨胀力关系为:恒体积>柔性等刚度>恒应力边界条件,最终膨胀率关系为:恒应力>柔性等刚度>恒体积边界条件;膨胀平衡极限(SEL)曲线可作为评价土体在复杂边界条件下水化时的最终体变和膨胀力的参考。研究结果对进一步认识土体的膨胀特性和指导高放废物处置库中缓冲/回填材料的设计具有一定参考意义。
The swelling behavior of buffer/backfill materials in high-level radioactive waste(HLW) repository is one of the significant indices evaluating their buffer/backfill properties. Due to the limitations of test apparatus, most of the previous swelling tests are performed under two simple extreme boundary conditions of constant volume(CV) and constant mean stress(CMS), which can not effectively reflect the complex stress-strain state in the repository. A new set of multi-boundary conditions dilatometer is designed to carry out a series of swelling tests under CV, CMS and constant stiffness(CS) boundary conditions. Based on this custom-made test apparatus, the swelling behavior of GMZ buffer/backfill materials is tested under complex boundary conditions. The results indicate that the developed test apparatus has the advantages of simple operation and stable performance, which can effectively stimulate various boundary conditions. The boundary conditions have an important influence on the ultimate swelling indices of samples. More specifically, the relationship between various boundary conditions and the corresponding swelling pressure is CV > CS > CMS, and the relationship between these conditions and the corresponding swelling strain is CMS > CS > CV. The swelling equilibrium limit(SEL) curve can be used as a reference for predicting the ultimate swelling strain and pressure of soils during hydration under complex boundary conditions. The test results have certain reference significance for further understanding the swelling behavior and guiding the design of buffer/backfill materials in HLW repository.
The swelling behavior of buffer/backfill materials in high-level radioactive waste(HLW) repository is one of the significant indices evaluating their buffer/backfill properties. Due to the limitations of test apparatus, most of the previous swelling tests are performed under two simple extreme boundary conditions of constant volume(CV) and constant mean stress(CMS), which can not effectively reflect the complex stress-strain state in the repository. A new set of multi-boundary conditions dilatometer is designed to carry out a series of swelling tests under CV, CMS and constant stiffness(CS) boundary conditions. Based on this custom-made test apparatus, the swelling behavior of GMZ buffer/backfill materials is tested under complex boundary conditions. The results indicate that the developed test apparatus has the advantages of simple operation and stable performance, which can effectively stimulate various boundary conditions. The boundary conditions have an important influence on the ultimate swelling indices of samples. More specifically, the relationship between various boundary conditions and the corresponding swelling pressure is CV > CS > CMS, and the relationship between these conditions and the corresponding swelling strain is CMS > CS > CV. The swelling equilibrium limit(SEL) curve can be used as a reference for predicting the ultimate swelling strain and pressure of soils during hydration under complex boundary conditions. The test results have certain reference significance for further understanding the swelling behavior and guiding the design of buffer/backfill materials in HLW repository.
引文
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[2]唐朝生,崔玉军,TANG A M,等.重塑COx泥岩在饱和过程中应力应变的演化规律[J].岩土工程学报,2010,32(8):1166-1171.(TANG Chao-sheng,CUI Yu-jun,TANG A M,et al.Stress and strain evolution of remoulded COx argillite during saturation[J]Chinese Journal of Geotechnical Engineering,2010,32(8):1166-1171.(in Chinese))
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[4]叶为民,潘虹,王琼,等.自由膨胀条件下高压实砂-膨润土混合物非饱和渗透特征[J].岩土工程学报,2011,33(6):869-874.(YE Wei-min,PAN Hong,WANG Qiong,et al.Saturated permeability of highly compacted sand-bentonite mixtures under unconfined conditions[J].Chinese Journal of Geotechnical Engineering,2011,33(6):869-874.(in Chinese))
[5]SUN D A,CUI H B,SUN W J.Swelling of compacted sand-bentonite mixtures[J].Applied Clay Science,2009,43(3):485-492.
[6]YE W M,CUI Y J,QIAN L X,et al.An experimental study of the water transfer through confined compacted GMZbentonite[J].Engineering Geology,2009,108(3/4):169-176.
[7]DELAGE P,HOWAT M D,CUI Y J.The relationship between suction and swelling properties in a heavily compacted unsaturated clay[J].Engineering Geology,1998,50(1/2):31-48.
[8]王志俭,刘泉声.密实砂-膨润土混合物膨胀特性的试验研究[J].岩土力学,2000,21(4):331-334.(WANG Zhi-jian,LIU Quan-sheng.Experimental study of swelling characteristics of compacted sand-bentonite mixture[J].Rock and Soil Mechanics,2000,21(4):331-334.(in Chinese))
[9]刘月妙,徐国庆,刘淑芬,等.中国高放废物处置库缓冲/回填材料压实膨胀特性研究[J].铀矿地质,2001,17(1):44-47.(LIU Yue-miao,XU Guo-qing,LIU Shu-fen,et al.Study on compactability and swelling property of buffer/backfill material for HLW repository[J].Uranium Geology,2001,17(1):44-47.(in Chinese))
[10]叶为民,SCHANZ T,钱丽鑫,等.高压实高庙子膨润土GMZ01的膨胀力特征[J].岩石力学与工程学报,2007,26(增刊2):3861-3865.(YE Wei-min,SCHANZ T,QIANLi-xin,et al.Characteristics of swelling pressure of densely compacted Gaomiaozi bentonite GMZ01[J].Chinese Journal of Rock Mechanics and Engineering,2007,26(S2):3861-3865.(in Chinese))
[11]秦冰,陈正汉,刘月妙,等.高庙子膨润土的胀缩变形特性及其影响因素研究[J].岩土工程学报,2008,30(7):1005-1010.(QIN Bing,CHEN Zheng-han,LIU Yue-miao,et al.Swelling-shrinkage behavior of Gaomiaozi bentonite[J].Chinese Journal of Geotechnical Engineering,2008,30(7):1005-1010.(in Chinese))
[12]TANG C S,TANG A M,CUI Y J,et al.Investigating the swelling pressure of compacted crushed Callovo-Oxfordian claystone[J].Physics and Chemistry of the Earth,Parts A/B/C,2011,36(17):1857-1866.
[13]张虎元,崔素丽,刘吉胜,等.混合型缓冲回填材料膨胀力试验研究[J].岩土力学,2010,31(10):3087-3095.(ZHANG Hu-yuan,CUI Su-li,LIU Ji-sheng,et al.Experimental study of swelling pressure of compacted bentonite-sand mixture[J].Rock and Soil Mechanics,2010,30(10):3087-3095.(in Chinese))
[14]CUI S L,ZHANG H Y,ZHANG M.Swelling characteristics of compacted GMZ bentonite-sand mixtures as a buffer/backfill material in China[J].Engineering Geology,2012(3):65-73.
[15]CUI Y J,TANG A M,LOISEAU C,et al.Determining the unsaturated hydraulic conductivity of a compacted sandbentonite mixture under constant-volume and free-swell conditions[J].Physics and Chemistry of the Earth,Parts A/B/C,2008,33:462-471.
[16]SUN D A,ZHANG J Y,ZHANG J R,et al.Swelling characteristics of GMZ bentonite and its mixtures[J].Applied Clay Science,2013,84(10):224-230.
[17]CHEN Y G,ZHU C M,YE W M,et al.Swelling pressure and hydraulic conductivity of compacted GMZ01 bentonite under salinization-desalinization cycle conditions[J].Applied Clay Science,2015,114:454-460.
[18]陈正汉,方祥位,朱元青,等.膨胀土和黄土的细观结构及其演化规律研究[J].岩土力学,2009,30(1):1-11.(CHEN Zheng-han,FANG Xiang-wei,ZHU Yuan-qing,et al.Research on meso-structures and their evolution laws of expansive soil and losses[J].Rock and Soil Mechanics,2009,30(1):1-11.(in Chinese))
[19]孙文静,孙德安,刘仕卿,等.高吸力下高庙子钙基膨润土的土水-力学特性[J].岩土工程学报,2014,36(2):346-353.(SUN Wen-jing,SUN De-an,LIU Shi-qing,et al.Hydro-mechanical behaviour of GMZ Ca-bentonite at high suctions[J].Chinese Journal of Geotechnical Engineering,2014,36(2):346-353.(in Chinese))
[20]唐朝生,黄立明,叶为民,等.GMZ01缓冲/回填材料在柔性边界条件下的膨胀特性[C]//第四届废物地下处置学术研讨会.南昌,2012.(TANG Chao-sheng,HUANG Li-ming,YE Wei-min,et al.Swelling deformation characteristic of GMZ01 backfill/buffer material under the soft boundary conditions[C]//Proceedings of the 4th Seminar on Geological Disposal of High-level Radioactive Nuclear Waste.Nanchang,2012.(in Chinese))
[21]SIEMENS G,BLATZ J A.Evaluation of the influence of boundary confinement on the behavior of unsaturated swelling clay soils[J].Canadian Geotechnical Journal,2009,46(3):339-356.
[22]LLORET A,VILLAR M V.Advances on the knowledge of the thermo-hydro-mechanical behavior of heavily compacted FEBEX bentonite[J].Physics and Chemistry of the Earth,Parts A/B/C,2007,32(8/9/10/11/12/13/14):701-715.
[23]WANG Q,TANG A M,CUI Y J,et al.Experimental study on the swelling behavior of bentonite/claystone mixture[J].Engineering Geology,2012,124(1):59-66.
[24]孙德安,孟德林,孙文静,等.两种膨润土的土-水特征曲线[J].岩土力学,2011,32(4):973-978.(SUN De-an,MENG De-lin,SUN Wen-jing,et al.Soil-water characteristic curves of two bentonites[J].Rock and Soil Mechanics,2011,32(4):973-978.(in Chinese))
[25]温志坚.中国高放废物处置库缓冲材料物理性能[J].岩石力学与工程学报,2006,25(4):794-800.(WEN Zhi-jian.Physical property of China’s buffer material for high-level radioactive waste repositories[J].Chinese Journal of Rock Mechanics and Engineering,2006,25(4):794-800.(in Chinese))
[26]陈志国,唐朝生,叶为民,等.水-力耦合条件下膨润土-砂混合物的体变特性研究[J].岩土力学,2017,38(4):1041-1051.(CHEN Zhi-guo,TANG Chao-sheng,YE Wei-min,et al.Volume change characteristics of bentonite-sand mixture under hydro-mechanical coupling condition[J].Rock and Soil Mechanics,2017,38(4):1041-1051.(in Chinese))
[27]叶为民,万敏,陈宝,等.干湿循环条件下高压实膨润土的微观结构特征[J].岩土工程学报,2011,33(8):1173-1177.(YE Wei-min,WAN Min,CHEN Bao,et al.Micro-structural behaviors of densely compacted GMZ01bentonite under drying/wetting cycles[J].Chinese Journal of Geotechnical Engineering,2011,33(8):1173-1177.(in Chinese))
[28]MOLLINS L H,STEWART D I,COUSENS T W.Predicting the properties of bentonite-sand mixtures[J].Clay Minerals,1996,31(2):243-252.
[29]NAVARRO V,MORENA G D L,YUSTRESá,et al.Predicting the swelling pressure of MX-80 bentonite[J].Applied Clay Science,2017,149:51-58.
[30]SCHANZ T,AL-BADRAN Y.Swelling pressure characteristics of compacted Chinese Gaomiaozi bentonite GMZ01[J].Soils and Foundations,2014,54(4):748-759.
[2]唐朝生,崔玉军,TANG A M,等.重塑COx泥岩在饱和过程中应力应变的演化规律[J].岩土工程学报,2010,32(8):1166-1171.(TANG Chao-sheng,CUI Yu-jun,TANG A M,et al.Stress and strain evolution of remoulded COx argillite during saturation[J]Chinese Journal of Geotechnical Engineering,2010,32(8):1166-1171.(in Chinese))
[3]YE W M,CHEN Y G,CHEN B,et al.Advances on the knowledge of the buffer/backfill properties of heavilycompacted GMZ bentonite[J].Engineering Geology,2010,116(1):12-20.
[4]叶为民,潘虹,王琼,等.自由膨胀条件下高压实砂-膨润土混合物非饱和渗透特征[J].岩土工程学报,2011,33(6):869-874.(YE Wei-min,PAN Hong,WANG Qiong,et al.Saturated permeability of highly compacted sand-bentonite mixtures under unconfined conditions[J].Chinese Journal of Geotechnical Engineering,2011,33(6):869-874.(in Chinese))
[5]SUN D A,CUI H B,SUN W J.Swelling of compacted sand-bentonite mixtures[J].Applied Clay Science,2009,43(3):485-492.
[6]YE W M,CUI Y J,QIAN L X,et al.An experimental study of the water transfer through confined compacted GMZbentonite[J].Engineering Geology,2009,108(3/4):169-176.
[7]DELAGE P,HOWAT M D,CUI Y J.The relationship between suction and swelling properties in a heavily compacted unsaturated clay[J].Engineering Geology,1998,50(1/2):31-48.
[8]王志俭,刘泉声.密实砂-膨润土混合物膨胀特性的试验研究[J].岩土力学,2000,21(4):331-334.(WANG Zhi-jian,LIU Quan-sheng.Experimental study of swelling characteristics of compacted sand-bentonite mixture[J].Rock and Soil Mechanics,2000,21(4):331-334.(in Chinese))
[9]刘月妙,徐国庆,刘淑芬,等.中国高放废物处置库缓冲/回填材料压实膨胀特性研究[J].铀矿地质,2001,17(1):44-47.(LIU Yue-miao,XU Guo-qing,LIU Shu-fen,et al.Study on compactability and swelling property of buffer/backfill material for HLW repository[J].Uranium Geology,2001,17(1):44-47.(in Chinese))
[10]叶为民,SCHANZ T,钱丽鑫,等.高压实高庙子膨润土GMZ01的膨胀力特征[J].岩石力学与工程学报,2007,26(增刊2):3861-3865.(YE Wei-min,SCHANZ T,QIANLi-xin,et al.Characteristics of swelling pressure of densely compacted Gaomiaozi bentonite GMZ01[J].Chinese Journal of Rock Mechanics and Engineering,2007,26(S2):3861-3865.(in Chinese))
[11]秦冰,陈正汉,刘月妙,等.高庙子膨润土的胀缩变形特性及其影响因素研究[J].岩土工程学报,2008,30(7):1005-1010.(QIN Bing,CHEN Zheng-han,LIU Yue-miao,et al.Swelling-shrinkage behavior of Gaomiaozi bentonite[J].Chinese Journal of Geotechnical Engineering,2008,30(7):1005-1010.(in Chinese))
[12]TANG C S,TANG A M,CUI Y J,et al.Investigating the swelling pressure of compacted crushed Callovo-Oxfordian claystone[J].Physics and Chemistry of the Earth,Parts A/B/C,2011,36(17):1857-1866.
[13]张虎元,崔素丽,刘吉胜,等.混合型缓冲回填材料膨胀力试验研究[J].岩土力学,2010,31(10):3087-3095.(ZHANG Hu-yuan,CUI Su-li,LIU Ji-sheng,et al.Experimental study of swelling pressure of compacted bentonite-sand mixture[J].Rock and Soil Mechanics,2010,30(10):3087-3095.(in Chinese))
[14]CUI S L,ZHANG H Y,ZHANG M.Swelling characteristics of compacted GMZ bentonite-sand mixtures as a buffer/backfill material in China[J].Engineering Geology,2012(3):65-73.
[15]CUI Y J,TANG A M,LOISEAU C,et al.Determining the unsaturated hydraulic conductivity of a compacted sandbentonite mixture under constant-volume and free-swell conditions[J].Physics and Chemistry of the Earth,Parts A/B/C,2008,33:462-471.
[16]SUN D A,ZHANG J Y,ZHANG J R,et al.Swelling characteristics of GMZ bentonite and its mixtures[J].Applied Clay Science,2013,84(10):224-230.
[17]CHEN Y G,ZHU C M,YE W M,et al.Swelling pressure and hydraulic conductivity of compacted GMZ01 bentonite under salinization-desalinization cycle conditions[J].Applied Clay Science,2015,114:454-460.
[18]陈正汉,方祥位,朱元青,等.膨胀土和黄土的细观结构及其演化规律研究[J].岩土力学,2009,30(1):1-11.(CHEN Zheng-han,FANG Xiang-wei,ZHU Yuan-qing,et al.Research on meso-structures and their evolution laws of expansive soil and losses[J].Rock and Soil Mechanics,2009,30(1):1-11.(in Chinese))
[19]孙文静,孙德安,刘仕卿,等.高吸力下高庙子钙基膨润土的土水-力学特性[J].岩土工程学报,2014,36(2):346-353.(SUN Wen-jing,SUN De-an,LIU Shi-qing,et al.Hydro-mechanical behaviour of GMZ Ca-bentonite at high suctions[J].Chinese Journal of Geotechnical Engineering,2014,36(2):346-353.(in Chinese))
[20]唐朝生,黄立明,叶为民,等.GMZ01缓冲/回填材料在柔性边界条件下的膨胀特性[C]//第四届废物地下处置学术研讨会.南昌,2012.(TANG Chao-sheng,HUANG Li-ming,YE Wei-min,et al.Swelling deformation characteristic of GMZ01 backfill/buffer material under the soft boundary conditions[C]//Proceedings of the 4th Seminar on Geological Disposal of High-level Radioactive Nuclear Waste.Nanchang,2012.(in Chinese))
[21]SIEMENS G,BLATZ J A.Evaluation of the influence of boundary confinement on the behavior of unsaturated swelling clay soils[J].Canadian Geotechnical Journal,2009,46(3):339-356.
[22]LLORET A,VILLAR M V.Advances on the knowledge of the thermo-hydro-mechanical behavior of heavily compacted FEBEX bentonite[J].Physics and Chemistry of the Earth,Parts A/B/C,2007,32(8/9/10/11/12/13/14):701-715.
[23]WANG Q,TANG A M,CUI Y J,et al.Experimental study on the swelling behavior of bentonite/claystone mixture[J].Engineering Geology,2012,124(1):59-66.
[24]孙德安,孟德林,孙文静,等.两种膨润土的土-水特征曲线[J].岩土力学,2011,32(4):973-978.(SUN De-an,MENG De-lin,SUN Wen-jing,et al.Soil-water characteristic curves of two bentonites[J].Rock and Soil Mechanics,2011,32(4):973-978.(in Chinese))
[25]温志坚.中国高放废物处置库缓冲材料物理性能[J].岩石力学与工程学报,2006,25(4):794-800.(WEN Zhi-jian.Physical property of China’s buffer material for high-level radioactive waste repositories[J].Chinese Journal of Rock Mechanics and Engineering,2006,25(4):794-800.(in Chinese))
[26]陈志国,唐朝生,叶为民,等.水-力耦合条件下膨润土-砂混合物的体变特性研究[J].岩土力学,2017,38(4):1041-1051.(CHEN Zhi-guo,TANG Chao-sheng,YE Wei-min,et al.Volume change characteristics of bentonite-sand mixture under hydro-mechanical coupling condition[J].Rock and Soil Mechanics,2017,38(4):1041-1051.(in Chinese))
[27]叶为民,万敏,陈宝,等.干湿循环条件下高压实膨润土的微观结构特征[J].岩土工程学报,2011,33(8):1173-1177.(YE Wei-min,WAN Min,CHEN Bao,et al.Micro-structural behaviors of densely compacted GMZ01bentonite under drying/wetting cycles[J].Chinese Journal of Geotechnical Engineering,2011,33(8):1173-1177.(in Chinese))
[28]MOLLINS L H,STEWART D I,COUSENS T W.Predicting the properties of bentonite-sand mixtures[J].Clay Minerals,1996,31(2):243-252.
[29]NAVARRO V,MORENA G D L,YUSTRESá,et al.Predicting the swelling pressure of MX-80 bentonite[J].Applied Clay Science,2017,149:51-58.
[30]SCHANZ T,AL-BADRAN Y.Swelling pressure characteristics of compacted Chinese Gaomiaozi bentonite GMZ01[J].Soils and Foundations,2014,54(4):748-759.