Determination of full-scale pore size distribution of Gaomiaozi bentonite and its permeability prediction  

作　　者：Jiangfeng Liu Shuaibing Song Xulou Cao Qingbin Meng Hai Pu Yangguang Wang Jianfeng Liu 

机构地区：[1]State Key Laboratory for Geomechanics and Deep Underground Engineering,School of Mechanics and Civil Engineering,China University of Mining and Technology,Xuzhou,221116,China [2]Key Laboratory of Deep Earth Science and Engineering,Ministry of Education,Sichuan University,Chengdu,610065,China

出　　处：《Journal of Rock Mechanics and Geotechnical Engineering》2020年第2期403-413,共11页岩石力学与岩土工程学报（英文版）

基　　金：support of the National Natural Science Foundation of China(Grant Nos.51809263);the Open Fund of Key Laboratory of Deep Earth Science and Engineering(Sichuan University)(Grant Nos.DESE201906 and DESE201907)。

摘　　要：Gaomiaozi(GMZ)bentonite is a potential buffer/backfill material for a deep geological disposal of highlevel radioactive waste.It has a wide pore size distribution(PSD)with sizes ranging from several nanometers to more than one hundred microns.Thus,properly characterizing the pore structures of GMZ bentonite is a challenging issue.In this study,pressure-controlled porosimetry(PCP),ratecontrolled porosimetry(RCP),and scanning electron microscopy(SEM)were used to investigate the PSD of GMZ bentonite,The results indicate that each method has its limitation,and a combined use of PCP and RCP is suitable to obtain the full-scale PSD of GMZ bentonite.Moreover,we also compared the full-scale PSD with nuclear magnetic resonance(NMR)result.It is found that there is no significant difference in the range of PSD characterization between NMR and mercury intrusion method(PCP and RCP).However,in a ce rtain range,the detection accuracy of NMR is higher than that of mercury injection method.Finally,permeability prediction based on PCP and SEM data was conducted,and both of the two methods were found to be able to predict the permeability.The combined method is effective to obtain the full-scale PSD of GMZ bentonite,which is the key to estimation of the sealing ability of bentonite buffer.

关 键 词：Gaomiaozi(GMZ)bentonite Pore size distribution(PSD) Pressure-controlled porosimetry(PCP) Rate-controlled porosimetry(RCP) Permeability High-level RADIOACTIVE waste 

分 类 号：TU43[建筑科学—岩土工程]