球(片)状石墨-膨润土混合物的渗透性能  

Permeability of Bentonite Mixed with Spherical(or Flake)Graphite

作　　者：祝雨 谈云志[1,2] 李辉[1,2] ZHU Yu;TAN Yunzhi;LI Hui(Yichang Key Laboratory of the Resources Utilization for Problematic Soils,China Three Gorges University,Yichang 443002,China;Hubei Key Laboratory of Disaster Prevention and Mitigation,China Three Georges University,Yichang 443002,China)

机构地区：[1]特殊土资源化利用宜昌市重点实验室(三峡大学),湖北宜昌443002 [2]防灾减灾湖北省重点实验室(三峡大学),湖北宜昌443002

出　　处：《三峡大学学报（自然科学版）》2024年第4期79-84,共6页Journal of China Three Gorges University：Natural Sciences

基　　金：国家自然科学基金项目(52279102)。

摘　　要：膨润土作为核废料处置库的缓冲材料需具有良好的导热性与隔离防渗能力.石墨具有高导热性,掺入膨润土中可以提高膨润土的导热率.因此,选择球状石墨和片状石墨,开展了不同掺入率下球(片)状石墨-膨润土混合物的渗透试验,研究了石墨掺入率与石墨形态对膨润土渗透性能的影响.结果表明:膨润土有效干密度相同时,随石墨掺入率增大,石墨-膨润土混合物中石墨颗粒易相互接触,形成架空孔隙,导致混合物的渗透系数增大.相同石墨掺入率20%下,片状石墨-膨润土混合物渗透系数(2.53×10^(-12) m/s)大于球状石墨-膨润土(9.4×10^(-13) m/s).究其原因,片状石墨与膨润土颗粒为点-面搭接,球状石墨与膨润土颗粒为点-点搭接,前者容易在片状石墨边缘形成未被充填的孔隙,最后演变成渗流通道,故球状石墨-膨润土混合物具有更好的防渗性能.As a buffer material for nuclear waste repository,bentonite should have good thermal conductivity,isolation and impermeability.Graphite has high thermal conductivity,which mixed into bentonite can improve the thermal conductivity of bentonite.Therefore,in this paper,flake graphite and spherical graphite were selected to test the effect of graphite morphology on the permeability of compacted bentonite.The results show that when the bentonite effective dry density is the same,with the increase of graphite content,the graphite particles are easy to contact with each other and form overhead pores,resulting in the increase of the hydraulic conductivity of the graphite-bentonite mixture.Moreover,the hydraulic conductivity(2.53×10^(-12) m/s)of flake graphite-bentonite mixture is higher than that of spherical graphite-bentonite mixture(9.4×10^(-13) m/s)at the same graphite content(20%).The reason is that flake graphite particles and bentonite particles are point-surface lap joints,and spherical graphite particles and bentonite particles are point-point lap joints.The former is easy to form unfilled pores on the edge of the graphite flake,and finally evolve into leakage passages.Therefore,the spherical graphite-bentonite mixture has better impermeability.

关 键 词：膨润土 石墨掺入率 石墨形态 渗透系数 有效干密度 

分 类 号：TU411.4[建筑科学—岩土工程]