高放废物地质处置库围岩的热传导特性是影响处置库布局和处置单元间距优化的关键因素之一。以北山花岗岩为研究对象,开展岩石在不同温度(200～800 ℃)处理后的热传导试验,探讨热处理对岩石导热系数的影响规律,分析其与常规物理参量的内在联系,揭示热处理岩石导热特性的饱水效应。研究结果表明:①岩样导热系数随热处理温度的升高而降低,导热系数的衰减速率在550～650 ℃阶段达到峰值;②随热处理温度的升高,岩样质量、干密度和纵波波速总体呈下降趋势,而岩样体积和孔隙率则逐渐增大,根据导热系数与纵波波速、孔隙率及干密度的关系,建立了热处理岩样导热系数的预测模型;③热处理前,饱水岩样的导热系数比干燥岩样增加了9.7%～12.1%,且两者呈近似线性增加的趋势;④热处理后,饱水岩样的导热系数随热处理温度的升高呈轻微下降趋势,且导热系数的饱水效应随孔隙率的增加呈近似线性增大。研究结果可为高放废物处置工程的设计和优化提供理论基础。
Abstract
In deep geological disposal of high-level radioactive waste (HLW), the thermal conductivity of host rock is a key factor in design because it has a direct impact on the repository layout and the optimization of distance between disposal elements. This study aims at investigating the thermal conductivity characteristics of Beishan granite treated with different temperatures ranging between 200 ℃ and 800 ℃. The influence of thermal treatment on thethermal conductivity of Beishan granite is analyzed, and the relations between thermal conductivity and other conventional physical parameters are also discussed. The effect of water saturation on the thermal conductivity is revealed as follows: 1) the thermal conductivity of Beishan granite specimens decays as treatment temperature rises, and the decay rate reaches peak value in the temperature range between 550 ℃ and 650 ℃; 2) as treatment temperature rises, the mass,dry density and P-wave velocity of specimens increase in general while the volume and porosity of specimens present an increasing trend; according to the relations between thermal conductivity and P-wave velocity, porosity, and dry density, respectively,models are established to predict the thermal conductivity of thermal-treated specimens; 3) before thermal treatment, the thermal conductivity values of saturated specimens increase by 9.7%-12.1% compared with those of dry ones,and the thermal conductivity of saturated specimens increases in an approximately linear trend with the increase of thermal conductivity of dry specimens; 4) on the other hand, when the thermal-treated specimens were saturated with water, the thermal conductivity shows a slightly decreasing trend as treatment temperature rises. We also found that the effect of water saturation on thermal conductivity increases with the increase of rock porosity, and this behavior can be described reasonably using a linear equation. The research achievements provide a theoretical basis for the design and optimization of deep geological disposal engineering.
关键词
北山花岗岩 /
热处理 /
热传导 /
高放废物地质处置 /
饱水效应
Key words
Beishan granite /
thermal treatment /
thermal conductivity /
geological disposal of high-level radioactive waste /
water saturation effect
{{custom_sec.title}}
{{custom_sec.title}}
{{custom_sec.content}}
参考文献
[1] 潘自强, 钱七虎. 高放废物地质处置战略研究[M]. 北京:原子能出版社, 2009.
[2] 王 驹, 范显华, 徐国庆, 等. 中国高放废物地质处置十年进展[M]. 北京:原子能出版社, 2004.
[3] HORAI K. Thermal Conductivity of Rock-forming Minerals[J]. Journal of Geophysical Research, 1971, 76(5): 1278-1308.
[4] CLAUSER C,HUENGES E. Thermal Conductivity of Rocks and Minerals[M]. Washington: American Geophysical Union, 1995.
[5] ROBERTSON E C, PECK D L. Thermal Conductivity of Vesicular Basalt from Hawaii[J]. Journal of Geophysical Research, 1974, 79(32):4875-4888.
[6] SUNDBERG J, BACK P E, ERICSSON L O, et al. Estimation of Thermal Conductivity and Its Spatial Variability in Igneous Rocks from in Situ Density Logging[J]. International Journal of Rock Mechanics and Mining Sciences, 2009, 46(6):1023-1028.
[7] CHO W J, KWON S, CHOI J W. The Thermal Conductivity for Granite with Various Water Contents[J]. Engineering Geology, 2009, 107(3/4):167-171.
[8] ZHAO X G, WANG J, CHEN F, et al. Experimental Investigations on the Thermal Conductivity Characteristics of Beishan Granitic Rocks for China’s HLW Disposal[J]. Tectonophysics, 2016, 683:124-137.
[9] SOMERTON W H, BOOZER G D. Thermal Characteristics of Porous Rocks at Elevated Temperatures[J]. Journal of Petroleum Technology, 1960, 12(6):77-81.
[10]SUN Q,LÜ C,CAO L W,et al. Thermal Properties of Sandstone after Treatment at High Temperature[J]. International Journal of Rock Mechanics and Mining Sciences, 2016, 85: 60-66.
[11]GÖRGÜLÜ K, DURUTÜRK Y S, DEMIRCI A, et al. Influences of Uniaxial Stress and Moisture Content on the Thermal Conductivity of Rocks[J]. International Journal of Rock Mechanics and Mining Sciences, 2008, 45(8): 1439-1445.
[12]DEMIRCI A, GÖRGÜLÜ K, DURUTÜRK Y S. Thermal Conductivity of Rocks and Its Variation With Uniaxial and Triaxial Stress[J]. International Journal of Rock Mechanics and Mining Sciences, 2004, 41(7): 1133-1138.
[13]CHAKI S, TAKARLI M, AGBODJAN W P. Influence of Thermal Damage on Physical Properties of a Granite Rock: Porosity, Permeability and Ultrasonic Wave Evolutions[J]. Construction and Building Materials, 2008, 22(7):1456-1461.
[14]胡少华, 章 光, 张 淼, 等. 热处理北山花岗岩变形特性与损伤力学分析[J]. 岩土力学, 2016, 37(12): 3427-3436.
[15]GUSTAFSSON S E. Transient Plane Source Techniques for Thermal Conductivity and Thermal Diffusivity Measurements of Solid Materials[J]. Review of Scientific Instruments, 1991, 62(3):797-804.
[16]ISRM. Suggested Method for Determining Water Content, Porosity, Density, Absorption and Related Properties and Swelling and Slake Durability Index Properties[J]. International Journal of Rock Mechanics and Mining Sciences, 1979, 16(2): 151-156.
[17]李继山. 油藏岩石热物理性质测试[J]. 大庆石油学院学报, 2009, 33(5):23-26.
[18]孙 强, 张志镇, 薛 雷, 等. 岩石高温相变与物理力学性质变化[J]. 岩石力学与工程学报, 2013, 32(5): 935-942.
[19]陈 旭, 俞 缙, 李 宏, 等. 不同岩性及含水率的岩石声波传播规律试验研究[J]. 岩土力学, 2013, 34(9): 2527-2533.
[20]YANG S Q, RANJITH P G, JING H W, et al. An Experimental Investigation on Thermal Damage and Failure Mechanical Behavior of Granite after Exposure to Different High Temperature Treatments[J]. Geothermics, 2017, 65:180-197.
[21]赵亚永, 魏 凯, 周佳庆, 等. 三类岩石热损伤力学特性的试验研究与细观力学分析[J]. 岩石力学与工程学报, 2017, 36(1):142-151.
[22]席道瑛. 花岗岩中矿物相变的物性特征[J]. 矿物学报, 1994, 14(3): 223-227.
[23]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.
[24]NAGARAJU P, ROY S. Effect of Water Saturation on Rock Thermal Conductivity Measurements[J]. Tectonophysics, 2014, 626:137-143.
[25]FUCHS S, SCHÜTZ F, FÖRSTER H J, et al. Evaluation of Common Mixing Models for Calculating Bulk Thermal Conductivity of Sedimentary Rocks:Correction Charts and New Conversion Equations[J]. Geothermics, 2013, 47:40-52.
[26]BOULANOUAR A, RAHMOUNI A, BOUKALOUCH M, et al. Determination of Thermal Conductivity and Porosity of Building Stone from Ultrasonic Velocity Measurements[J]. Geomaterials, 2013, 3(4): 138-144.
PDF(4746 KB)
