膨润土胶体在处置库围岩裂隙中的扩散模型研究  

Diffusion modeling of bentonite colloids in fractures of repository surrounding rocks

作　　者：陈宝[1,2] 向平 邓荣升 CHEN Bao;XIANG Ping;DENG Rong-sheng(College of Civil Engineering,Tongji University,Shanghai 200092,China;Key Laboratory of Geotechnical and Underground Engineering of Ministry of Education,Tongji University,Shanghai 200092,China)

机构地区：[1]同济大学土木工程学院,上海200092 [2]同济大学岩土及地下工程教育部重点实验室,上海200092

出　　处：《岩土力学》2024年第2期433-442,共10页Rock and Soil Mechanics

基　　金：国家自然科学基金(No.42272324)。

摘　　要：为了预测膨润土胶体在甘肃北山高放废物深地质处置库围岩裂隙中的扩散过程,提出了综合考虑膨润土胶体颗粒自重与水化力的扩散模型。研究了钠离子浓度、水化力、胶体颗粒自重以及蒙脱石体积分数对膨润土胶体的扩散过程和扩散系数的影响。研究结果表明:随着钠离子浓度的增加,膨润土胶体的扩散速率与扩散距离均减小。胶体颗粒自重越大,对扩散的影响越大。随着扩散的进行,水化力对扩散的影响逐渐减小,范德华力和扩散双电层力对扩散的影响逐渐增大,膨润土胶体的扩散系数整体表现为先减小后增大。当蒙脱石体积分数较小时(φ<0.45),随着钠离子浓度的增加,扩散系数整体上逐渐增大;当蒙脱石体积分数较大时(φ>0.45),钠离子浓度对扩散系数的影响较小。In order to predict the diffusion process of bentonite colloids in the fractures of surrounding rocks in the deep geological repository of high-level radioactive waste in Beishan,Gansu,a diffusion model that integrates the self-weight of bentonite colloid particles and hydration force is proposed.The effects of sodium ion concentration,hydration force,self-weight of colloid particles,and volume fraction of montmorillonite on the diffusion process and diffusion coefficient of bentonite colloids were investigated.The results show that both the diffusion rate and diffusion distance of bentonite colloids decrease with the increase of sodium ion concentration.The greater the self-weight of colloidal particles,the more significant their impact on diffusion.As the diffusion proceeds,the influence of hydration force on diffusion gradually decreases,while the influence of van der Waals force and diffusion double-layer force gradually increases,and in general,the diffusion coefficient of bentonite colloids decreases first and then increases.When the volume fraction of montmorillonite is small(φ <0.45),the diffusion coefficient generally increases with the increase of sodium ion concentration;when the volume fraction of montmorillonite is large(φ >0.45),the influence of sodium ion concentration on the diffusion coefficient is relatively small.

关 键 词：膨润土胶体 胶体扩散模型 扩散系数 颗粒自重 水化力 

分 类 号：TU443[建筑科学—岩土工程]