摘要
混合型缓冲砌块作为高放废物地质处置库的缓冲屏障具有良好的导热性能。将高庙子(GMZ)膨润土和标准石英砂混合,依据正交试验原则,控制掺砂率Rs=30%,设置含水率变化为7.0%、11.0%、15.0%,干密度变化为1.60、1.70、1.80g/cm^3,采用半自动化液压机压制成大型缓冲砌块。对砌块进行切割分解,开展热传导试验,建立含水率和干密度与导热性能的关系,了解导热性能的空间分布特征。试验结果表明,随着含水率和干密度的增大,混合型缓冲砌块导热系数显著增大,大致呈线性关系,且平均值均大于国际原子能机构国际原子能机构(IAEA)推荐的导热系数下限值0.8 W/m·K,满足推荐要求;热扩散系数先略微减小再增大,总体也呈增大趋势。对混合型缓冲砌块导热系数的空间分布及均匀性分析发现,砌块四周边缘部位的导热系数比中间部位的波动略大,但总体差异性及非均匀性不明显。采用t检验法对混合型缓冲砌块导热系数均匀性进行检验,发现砌块满足均匀性检验条件,试样均匀。用Johansen模型从物理指标可以预测混合型缓冲砌块的导热系数,偏差在±10%以内。
The hybrid buffer block as a buffer barrier requires good thermal conductivity for geological storage of high-level waste(HLW).In this study,Gaomiaozi(GMZ)bentonite was mixed with standard quartz sand,and the sand mixing rate Rs was controlled at 30%according to the orthogonal test principle.The moisture contents were set at 7.0%,11.0%,and 15.0%,and dry densities were set at 1.60,1.70 and 1.80 g/cm3,respectively.A large buffer block was pressed with a semi-automatic hydraulic press.The heat transfer test was conducted on the cut and decomposed block.The relationship among the moisture content,dry density and thermal conductivity was established,and the spatial distribution characteristics of thermal conductivity were analyzed.Test results show that the thermal conductivity of buffer blocks increase linearly with the increases in water contents and dry densities.The mean value of thermal conductivity more than 0.8 W/m∙K satisfies the requirement recommended by International Atomic Energy Agency(IAEA).The thermal diffusion coefficient slightly decreases first and then increases,and the overall trend also increases.The spatial distribution and uniformity of the thermal conductivity of the hybrid buffer block were also analyzed.It is found that the thermal conductivity of the block edge fluctuates larger than that of the middle part,but the overall difference and non-uniformity are not obvious.The t-test method was used to test the uniformity of thermal conductivity of the hybrid buffer block.The test results show the block satisfies the uniformity test condition and the sample is uniform.Data analysis shows that the thermal conductivity of the hybrid buffer block can be predicted from the physical index using the Johansen model with a deviation of±10%.
作者
张虎元
赵秉正
童艳梅
ZHANG Hu-yuan;ZHAO Bing-zheng;TONG Yan-mei(Key Laboratory of Mechanics on Disaster and Environment in Western China,the Ministry of Education,Lanzhou University,Lanzhou,Gansu 730000,China;School of Civil Engineering and Mechanics,Lanzhou University,Lanzhou,Gansu 730000,China;School of Advanced Materials and Nanotechnology,Xidian University,Xi’an,Shaanxi 710000,China)
出处
《岩土力学》
EI
CAS
CSCD
北大核心
2020年第S01期1-9,18,共10页
Rock and Soil Mechanics
基金
国家自然科学基金项目(No.41672261)
中央高校基本科研业务费专项(No.lzujbky-2016-k15,No.lzujbky-2017-ct02)
