曾召田, 曹珊珊, 林铭宇,等.碱-热条件下压实膨润土缓冲材料持水性能演化及其微观机制[J].河南理工大学学报（自然科学版）,2026,45(4):180-189.

ZENG Z T, CAO S S, LIN M Y,et al.Evolution of water retention performance and its micromechanism in compacted bentonite buffer materials under alkali-thermal conditions[J].Journal of Henan Polytechnic University(Natural Science) ,2026,45(4):180-189.

碱-热条件下压实膨润土缓冲材料持水性能演化及其微观机制

曾召田1, 曹珊珊1, 林铭宇1, 李龚颜1, 梁珍1,2

1.桂林理工大学 广西岩土力学与工程重点实验室，广西 桂林 541004;2.新疆交通规划勘察设计研究院有限公司，新疆 乌鲁木齐  830006

摘要: 目的 深地质处置库持续运营期间，围岩中地下水会不断侵蚀衬砌混凝土使其逐渐老化、分解产生强碱性溶液，而位于处置库中的核废物不断衰变放热，使库内环境温度不断升高，在这种碱-热条件影响下，膨润土缓冲层材料的持水性能将发生改变。为保障缓冲屏障性能的有效性，针对其持水性能进行深入研究。  方法采用饱和盐溶液法测定碱-热条件下压实MX-80膨润土试样的持水性能（饱和度S_r -吸力s）变化曲线，分别探讨碱液浓度C_NaOH（0，0.1，0.3，1.0 mol/L）和温度T（20，60，90 ℃）对其持水性能的影响规律，并结合课题组前期XRD和MIP试验结果分析碱液浓度和温度对持水性能的影响机理。  结果结果表明：碱-热条件下，压实膨润土试样的持水性能随碱液浓度和温度的升高而减弱，且碱液浓度和温度越高，试样的持水性能降低越显著；碱-热条件下膨润土持水性能的变化是由蒙脱石含量的改变引起的，温度加速了碱液对蒙脱石的溶蚀，间接引起持水性能下降；膨润土的持水性能随蒙脱石含量的减少而递减，二者具有明显的线性关系。  结论深入探讨了碱-热条件下膨润土的持水性能变化规律，研究结果可为渗透系数预测、工程屏障性能评价提供科学的数据支撑。

关键词:MX-80膨润土;碱-热条件;持水性能;矿物成分;微观机制

doi:10.16186/j.cnki.1673-9787.2024110058

基金项目:国家自然科学基金资助项目（42167020）；广西自然科学基金资助项目（2023GXNSFAA026187）

收稿日期:2024/10/27

修回日期:2024/12/31

出版日期:2026/06/17

Evolution of water retention performance and its micromechanism in compacted bentonite buffer materials under alkali-thermal conditions

Zeng Zhaotian1, Cao Shanshan1, Lin Mingyu1, Li Gongyan1, Liang Zhen1,2

1.Guangxi Key Laboratory of Geotechnical Mechanics and Engineering， Guilin University of Technology，Guilin  541004，Guangxi， China;2.Xinjiang Transportation Planning Survey and Design Institute Co.， Ltd.， Urumqi  830006， Xinjiang， China

Abstract: Objectives During the continuous operation of a deep geological repository， groundwater in the surrounding rock continuously erodes the lining concrete， causing it to gradually age and decompose， producing highly alkaline solutions. Meanwhile， the nuclear waste in the repository continuously decays and generates heat， steadily raising the temperature inside the repository environment. Under these alkali-thermal conditions， the water retention performance of the bentonite buffer layer material will change. To ensure the effectiveness of the buffer barrier performance， an in-depth investigation into its water retention performance was conducted.  Methods The saturated salt solution method was employed to determine the water retention performance curves （degree of saturation S_r vs. suction s） of compacted MX80 bentonite specimens under alkali-thermal conditions. The effects of alkali solution concentration （C_NaOH=0， 0.1， 0.3， 1.0mol/L） and temperature （T=20， 60， 90℃） on the water retention performance were investigated. Combined with previous XRD and MIP test results from the research group， the mechanisms by which alkali concentration and temperature affect water retention performance were analyzed. Results The results indicate that under alkali-thermal conditions， the water retention performance of compacted bentonite specimens decreases with increasing alkali concentration and temperature. The higher the alkali concentration and temperature， the more significantly the water retention performance degrades. The change in water retention performance of bentonite under alkali-thermal conditions is caused by the alteration of montmorillonite content. Temperature accelerates the alkali-induced dissolution of montmorillonite， indirectly leading to a decline in water retention performance. The water retention performance of bentonite decreases with the reduction of montmorillonite content， and there is a clear linear relationship between the two. Conclusions The evolution of water retention performance of bentonite under alkali-thermal conditions was thoroughly discussed. The research results can provide scientific data support for the prediction of hydraulic conductivity and the performance evaluation of engineering barriers.

Key words:MX-80 bentonite;alkali-thermal condition;water retention performance;mineral composition;micromechanism