对我国高放废物地质处置地下实验室场址的甘肃北山花岗岩分别进行不同温度下(25、60、90、120、200、300 ℃)的巴西劈裂试验,通过实时声发射监测、主断面分析以及颗粒流程序数值模拟,研究了岩样的裂隙扩展过程。结果表明:①120 ℃时温度对花岗岩存在显著强化效应,其他温度下花岗岩强度较常温下降低;②声发射数据显示中等温度(60~120 ℃)荷载下花岗岩产生的裂隙数量和尺度随着温度升高而增大,因此消耗更多的加载能量,使得花岗岩强度逐渐增大;③受长石、石英和云母的热力学性质差异影响,在室温至120 ℃范围,花岗岩断面裂隙随着温度升高更趋于沿着长石颗粒的边界扩展,120 ℃后非长石颗粒边界的裂隙占比开始上升;④基于花岗岩表面矿物实际分布建立了PFC2D模型并进行模拟试验,可知温度能降低矿物颗粒间的粘结强度,使得岩石更易发生破裂。
Abstract
Brazilian splitting tests were conducted on Beishan granite (the potential host rock for China’s high-level radioactive waste repository) at different temperatures (25 ℃,60 ℃,90 ℃,120 ℃,200 ℃,and 300 ℃).The cracking process of granites was investigated using acoustic emission (AE),section analysis and particle flow code (PFC).Results reveal that:1) Temperature at 120℃ has a significant strengthening effect on granite,while the strength of granite at other temperatures is lower than that at 25 ℃.2) The AE data shows that the number and size of cracks in granite both increase with rising temperature in mild temperature range (60 ℃~120 ℃),which consumes more energy produced by loading and gradually improves the strength of granite.(3) Affected by the differences in thermodynamic properties of feldspar,quartz and mica,cracks of granite tend to propagate along the boundary of feldspar with the increase of temperature between 25 ℃ and 120 ℃.When temperature is higher than 120 ℃,the proportion of cracks at the boundary of non-feldspar particles begins to rise.(4) PFC2D model was established based on the distribution of minerals on granite surface,and the simulation suggest that temperature could reduce the bond strength between mineral particles and makes the rock more prone to fracture.
关键词
北山花岗岩 /
巴西劈裂试验 /
温度 /
裂隙 /
声发射 /
K均值聚类法 /
PFC2D
Key words
Beishan granite /
Brazilian splitting test /
temperature /
cracks /
acoustic emission /
K-means clustering /
PFC2D
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参考文献
[1] 王 驹,陈伟明,苏 锐,等.高放废物地质处置及其若干关键科学问题[J].岩石力学与工程学报,2006,25(4):801-812.
[2] SIZGEK G D.Three-dimensional Thermal Analysisof In-floor Type Nuclear Waste Repository for a Ceramic Waste Form[J].Nuclear Engineering and Design,2004,235(1):101-109.
[3] 刘海涛,周 辉,胡大伟,等.核废料处置库热-力耦合数值模拟研究[J].现代隧道技术,2019,56(1):47-55,71.
[4] 徐少波.核废料处置库近场花岗围岩温度场模拟研究[D].成都:成都理工大学,2016.
[5] 周祥运,孙德安,罗 汀.核废料处置库近场温度半解析研究[J].岩土力学,2020,41(增刊1):246-254.
[6] CHO W J,KIM J S,CHOI H J.Hydrothermal Modelingfor the Efficient Design of Thermal Loading in a Nuclear Waste Repository[J].Nuclear Engineering and Design,2014,276:241-258.
[7] 赵阳升,孟巧荣,康天合,等.显微CT试验技术与花岗岩热破裂特征的细观研究[J].岩石力学与工程学报,2008,27(1):28-34.
[8] 张志镇,高 峰,刘治军.温度影响下花岗岩冲击倾向及其微细观机制研究[J].岩石力学与工程学报,2010,29(8):1591-1602.
[9] DWIVEDI R D,GOEL R K,PRASAD V V R,et al.Thermo-mechanical Properties of Indian and Other Granites[J].International Journal of Rock Mechanics and Mining Sciences,2007,45(3):303-315.
[10] YIN T B,LI X B,CAO W Z,et al.Effects of Thermal Treatment on Tensile Strength of Laurentian Granite Using Brazilian Test[J].Rock Mechanics and Rock Engineering,2015,48(6):2213-2223.
[11] GLOVER P,BAUD P,DAROT M,et al.α/β Phase Transition in Quartz Monitored Using Acoustic Emissions[J].Geophysical Journal International,1995,120:775-782.
[12] 陈世万,杨春和,刘鹏君,等.北山花岗岩热破裂室内模拟试验研究[J].岩土力学,2016,37(增刊1):547-556.
[13] DAVID C,MENéNDEZ B,DAROT M.Influence of Stress-induced and Thermal Cracking on Physical Properties and Microstructure of La Peyratte Granite[J].International Journal of Rock Mechanics and Mining Sciences,1999,36(4):433-448.
[14] SHAO S S,RANJITH P G,WASANTHA P L P,et al.Experimental and Numerical Studies on the Mechanical Behaviour of Australian Strathbogie Granite at High Temperatures:An Application to Geothermal Energy[J].Geothermics,2015,54:96-108.
[15] 梁源凯,冯增朝,白 骏,等.热力耦合作用下花岗岩热破裂特征的颗粒流分析[J].水电能源科学,2020,38(1):127-130,93.
[16] TIAN W L,YANG S Q,HUANG Y H,et al.Mechanical Behavior of Granite with Different Grain Sizes after High-temperature Treatment by Particle Flow Simulation[J].Rock Mechanics and Rock Engineering,2019,53(3):1-17.
[17] WANG F,KONIETZKY H,FRüHWIRT T,et al.Laboratory Testing and Numerical Simulation of Properties and Thermal-induced Cracking of Eibenstock Granite at Elevated Temperatures[J].Acta Geotechnica,2020,15(8):2259-2275.
[18] LIU H,ZHANG K,SHAO S S,et al.Numerical Investigation on the Cooling-related Mechanical Properties of Heated Australian Strathbogie Granite Using Discrete Element Method[J].Engineering Geology,2020,264:105371.
[19] GAUTAM P K,VERMA A K,JHA M K,et al.Effect of High Temperature on Physical and Mechanical Properties of Granite[J].Journal of Applied Geophysics,2018:159:460-474.
[20] KUMARI W G P,RANJITH P G,PERERA M S A,et al.Temperature-dependent Mechanical Behaviour of Australian Strathbogie Granite with Different Cooling Treatments[J].Engineering Geology,2017,229:31-44.
[21] 吴阳春,郤保平,王 磊,等.高温后花岗岩的物理力学特性试验研究[J].中南大学学报(自然科学版),2020,51(1):193-203.
[22] FEI Y.Thermal Expansion[M] //AHRENS T J.Mineral Physics & Crystallography:A Handbook of Physical Constants.Washington:American Geophysical Union,1995.
[23] SIEGESMUND S,MOSCH S,SCHEFFZUK C H,et al.The Bowing Potential of Granitic Rocks:Rock Fabrics,Thermal Properties and Residual Strain[J].Environmental Geology,2008,55:1437-1448.
[24] LOUIS N Y W,ZHANG Y H,WU Z J.Rock Strengthening or Weakening upon Heating in the Mild Temperature Range[J].Engineering Geology,2020,272:105619.
[25] 王昊雷.K均值聚类算法研究与应用[D].哈尔滨:哈尔滨工程大学,2015.
[26] WANNE T.Bonded-particle Modelingof Thermally Induced Damage in Rock[J].Christianity & Culture,2009,26(3):251-258.
[27] 闵 明,张 强,蒋斌松,等.实时高温下北山花岗岩劈裂试验及声发射特性[J].长江科学院院报,2020,37(3):108-113.
[28] 邓申缘,姜清辉,商开卫,等.高温对花岗岩微结构及渗透性演化机制影响分析[J].岩土力学,2021,42(6):1601-1611.
基金
国家自然科学基金项目(41902301);岩土力学与工程国家重点实验室开放基金课题(Z018023)
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