Feasibility of compacted attapulgite/diatomite amended clayey soils as gas barrier materials  

作　　者：Heng Zhuang Wei-Yi Xia Jia-Ming Wen Min Wang Ying-Zhen Li Ning-Jun Jiang Konstantin S.Rodygin Yan-Jun Du 

机构地区：[1]Jiangsu Key Laboratory of Low Carbon and Sustainable Geotechnical Engineering,Institute of Geotechnical Engineering,Southeast University,Nanjing,211189,China [2]Jiangsu Province Ecology and Environment Protection Engineering Research Center of Groundwater Pollution Prevention and Control,Jiangsu Environmental Engineering Technology Co.,Ltd.,Nanjing,210036,China [3]Zijin(Changsha)Engineering Technology Co.,Ltd.,Changsha,410006,China [4]Institute of Chemistry,Saint Petersburg State University,Stary Petergof,198504,Russia

出　　处：《Journal of Rock Mechanics and Geotechnical Engineering》2024年第9期3707-3717,共11页岩石力学与岩土工程学报（英文版）

基　　金：the funding support from the National Natural Science Foundation of China(Grant No.42177133);the Primary Research and Development Plan of Jiangsu Province(Grant No.BE2022830);the Primary Research and Development Plan of Anhui Province(Grant No.2023t07020018).

摘　　要：Compacted clay liners are extensively used as barriers to control the upward diffusion of vapors of volatile or semi-volatile organic contaminants released from unsaturated contaminated soils at industrycontaminated sites.This study aimed to investigate the gas diffusion barrier performance of compacted clayey soils amended with three agents including attapulgite and diatomite individually,and attapulgite/diatomite mixture.The properties including water retention,volumetric shrinkage,gas diffusion,and unconfined compressive strength were evaluated through a series of laboratory tests of amended compacted clayey soils.The results demonstrate that the decrease in volume proportions of interaggregate pores leads to an increase in unconfined compressive strength(qu).Both hydrophilic groups and microstructures of attapulgite and diatomite result in an increase in water retention percent(Wt)of compacted clayey soil specimens after amendment regardless of the type of agent or initial water content(w0).Furthermore,the ratio of the gas diffusion coefficient(De)to the gas diffusion coefficient in the air(Da)was significantly reduced owing to a decrease in volume proportions of inter-aggregate pores,hydrophilic group,and microstructures of attapulgite and diatomite.Scanning electron microscope analyses revealed that rod-shaped attapulgite filled the inter-aggregate pores formed by clay particles,whereas the disc-shaped diatomite particles,characterized by micropores,failed to obstruct the interaggregate pores due to their larger particle size.Mercury intrusion porosimetry(MIP)analyses showed a reduction in pore volume in the inter-aggregate pores,leading to a reduction in the total pore volume for both the attapulgite and attapulgite/diatomite mixture amended clays,which is in accordance with the scanning electron microscope(SEM)results.The findings are pertinent to the practical application of compacted clay liners as gas barriers against the upward migration of volatile or semi-volatile organic contaminants at contaminate

关 键 词：Compacted clay liner Attapulgite/diatomite mixture Diffusion barrier Water retention 

分 类 号：TU43[建筑科学—岩土工程]