Water retention characteristics of GMZ bentonite with different montmorillonite contents and dry densities
ZHANG Qi1, 2*, WANG Ju1, LIU Jiangfeng2, ZONG Zihua1, CAO Shengfei1, XIE Jingli1, CHENG Jianfeng1
(1. CAEA Innovation Center for Geological Disposal of High-Level Radioactive Waste, Beijing Research Institute of Uranium Geology, Beijing 100029, China; 2. State Key Laboratory of Intelligent Construction and Healthy Operation and Maintenance of Deep Underground Engineering, China University of Mining and Technology, Xuzhou, Jiangsu 221116, China)
Abstract：The investigation of the water retention characteristics of Gaomiaozi (GMZ) bentonite is crucial for selecting buffer/backfill materials and designing engineering barrier systems for high-level radioactive waste (HLW) geological disposal. This study examined the water retention properties of GMZ bentonite with varying montmorillonite contents and dry densities. The Nuclear Magnetic Resonance (NMR) technique was utilized to analyze the microscopic characteristics and mechanisms of water distribution in GMZ bentonite under different conditions. The results indicated that the effect of montmorillonite content on the water retention properties of GMZ bentonite was dependent on the controlled suction during the tests. When the controlled suction was below 113.8 MPa, the volumetric change rate and water content of the samples increased gradually with higher montmorillonite content. However, no significant correlation was found between increases in montmorillonite content and volumetric change rate or water content at controlled suctions exceeding 113.8 MPa. Throughout the suction range of 2.7 MPa to 367.8 MPa investigated in this study, the dry density of GMZ bentonite did not significantly influence its water retention characteristics. The water retention curves of GMZ bentonite with varying montmorillonite contents and dry densities were well fitted by the Van Genuchten model. Finally, NMR tests were conducted on samples following the water retention tests, which confirmed the findings obtained from the water retention characteristic tests of GMZ bentonite.
张 奇1，2*，王 驹1，刘江峰2，宗自华1，曹胜飞1，谢敬礼1，成建峰1. 不同蒙脱石含量及干密度高庙子膨润土持水特性[J]. 岩石力学与工程学报, 2026, 45(4): 1241-1249.
ZHANG Qi1, 2*, WANG Ju1, LIU Jiangfeng2, ZONG Zihua1, CAO Shengfei1, XIE Jingli1, CHENG Jianfeng1. Water retention characteristics of GMZ bentonite with different montmorillonite contents and dry densities. , 2026, 45(4): 1241-1249.
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