γ辐照老化对高庙子天然钠基膨润土力学强度和变形特性影响研究  

Influences of γ-rays irradiation on strength and deformation behaviors of Gaomiaozi Na-bentonite

作　　者：刘鹏[1,2,3] 刘俊新[1,2,4] 冒海军 杨仲田[5] 刘伟[5] 巫尚蔚[6] 王文清[3] LIU Peng LIU Jun-xin MAO Hai-jun YANG Zhong-tian LIU Wei WU Shang-wei WANG Wen-qing(School of Civil Engineering and Architecture, Southwest University of Science and Technology, Mianyang, Sichuan 621010, China Key Laboratory of Shock and Vibration of Engineering Materials and Structures of Sichuan Province, Mianyang, Sichuan 621010, China State Key Laboratory of Geomechanics and Geotechnical Engineering, Institute of Rock and Soil Mechanics, Chinese Academy of Sciences, Wuhan0 Hubei 430071, China Key Laboratory on Geological Disposal of High-Level Radioactive Waste of China National Nuclear Corporation, China Institute for Radiation Protection, Taiyuan, Shanxi 030006, China College of Resources and Environment Science, Chongqing University, Chongqing 400044, China Southern China Branch of CCCC Tunnel Engineering Co., Ltd., Guangzhou, Guangdong 510000, China)

机构地区：[1]西南科技大学土木工程与建筑学院,四川绵阳621010 [2]西南科技大学工程材料与结构冲击振动四川省重点实验室,四川绵阳621010 [3]中交隧道工程局有限公司华南分公司,广东广州510000 [4]中国科学院武汉岩土力学研究所岩土力学与工程国家重点实验室,湖北武汉430071 [5]中国辐射防护研究院中核高放废物地质处置评价技术重点实验室,山西太原030006 [6]重庆大学资源及环境科学学院,重庆400044

出　　处：《岩土力学》2017年第10期2949-2956,共8页Rock and Soil Mechanics

基　　金：十三五国家重点研发计划(No.2017YFC0804600);四川省科技支撑计划项目(No.2016GZ0157);西南科技大学研究生创新基金资助(No.16ycx078)~~

摘　　要：为探究高放核废物深地质处置缓冲材料的长期稳定性,以内蒙古高庙子(GMZ)天然钠基膨润土为研究对象,揭示了γ辐照老化作用对高压实天然钠基膨润土样品力学强度和变形特性的影响。采用钴源在室温下对该膨润土进行不同累积剂量的辐照作用,分析了辐照前、后膨润土的矿物成分变化,并开展了三轴剪切以及膨胀变形试验。结果表明:γ辐照老化作用引起膨润土部分矿物成分的变化,蒙脱石微观结构稳定性降低并转化为更稳定的硅酸盐和硅铝酸盐矿物;膨润土经过辐照作用后剪切强度有所增长且随辐照剂量增大,矿物成分发生了变化,同等围压下膨润土的剪切峰值强度逐渐提高;随着围压的增大,强度增长的幅度逐渐变缓,辐照剂量对强度的影响减弱,表明围压对膨润土强度的增长有一定的抑制作用;由于辐照后蒙脱石的含量减少,膨润土的膨胀变形性能相应减弱,即膨胀力、自由膨胀应变、有荷膨胀应变等指标降低。Natural Na-bentonite, from Gaomiaozi（GMZ）, Inner Mongolia, was tested to study the long-term stability of buffer/backfilling material for high-level radioactive waste geological disposal,. This paper analyzed the effects of γ-rays irradiation on the strength and deformation characteristics of densely compacted Na-bentonite sample. The bentonite was irradiated by cobalt source at different cumulative irradiation doses in laboratory. The mineral composition changes into some more stable silicate and aluminosilicate minerals after irradiation. Then the triaxial shear test and swelling test show that the stability of the microstructure of montmorillonite decreases, and the shear strength and the peak shear strength of bentonite increase with the irradiation dosage under the same confining pressure, due to the change in the mineral composition. With the increase of confining pressure, the strength trend increases gradually slowly, and the effect of irradiation dose on the strength turns to be weaken. It indicates that the confining pressure inhibits the strength increase of bentonite sample. Due to reduction of montmorillonite after irradiation, the swelling deformation property is weakened. The performance is the decrease of the expansion force, free swelling strain, load swelling strain and other indicators.

关 键 词：辐照老化 钠基膨润土 蒙脱石 力学强度 膨胀性能 

分 类 号：TU443[建筑科学—岩土工程]