干湿循环作用下地聚物隔离墙材料渗透特性演化及微观机制研究  

Evolution of permeability characteristics and micro-mechanism of geopolymer cutoff wall materials under dry-wet cycling

作　　者：薛钦培 陈宏信 冯世进[1,3] 刘晓轩 谢伟 XUE Qin-pei;CHEN Hong-xin;FENG Shi-jin;LIU Xiao-xuan;XIE Wei(Department of Geotechnical Engineering,Tongji University,Shanghai 200092,China;Key Laboratory of Geotechnical and Underground Engineering of Ministry of Education,Tongji University,Shanghai 200092,China;State Key Laboratory of Disaster Reduction in Civil Engineering,Tongji University,Shanghai 200092,China;Baowu Group Environmental Resources Technology Co.,Ltd.,Shanghai 201999,China;PowerChina Huadong Engineering Corporation Limited,Hangzhou,Zhejiang 311122,China)

机构地区：[1]同济大学地下建筑与工程系,上海200092 [2]同济大学岩土及地下工程教育部重点实验室,上海200092 [3]同济大学土木工程防灾减灾全国重点实验室,上海200092 [4]宝武集团环境资源科技有限公司,上海201999 [5]中国电建集团华东勘测设计研究院有限公司,浙江杭州311122

出　　处：《岩土力学》2025年第3期811-820,共10页Rock and Soil Mechanics

基　　金：国家重点研发计划项目(No.2023YFC3707904);国家自然科学基金面上项目(No.42077250,No.42277148)。

摘　　要：竖向隔离墙是限制污染物迁移最有效的技术之一,已被广泛用于污染土壤和地下水的现场管控。在干湿循环作用下,传统隔离墙材料极易发生性能劣化,导致其服役寿命显著缩短。通过一系列宏微观试验,研究了干湿循环作用下钠基膨润土、氧化镁、微胶囊3种改性材料对粉煤灰基地聚物隔离墙材料渗透特性演化和微观结构的影响。研究表明:不同地聚物隔离墙材料养护28 d后无侧限抗压强度和渗透系数均满足水泥基隔离墙的防渗设计要求,分别可以达到6.62 MPa和4.73×10^(-11)m/s;不含改性材料的试样在1次干湿循环后渗透系数超过1×10^(-8)m/s,而含有改性材料的渗透系数在5次循环后仍能达到设计要求;3种改性材料通过影响小孔(<0.05μm)、中孔[0.05μm,0.10μm]和大孔(>0.10μm)所占的比例,可以有效提高地聚物隔离墙材料在干湿循环条件下的防渗性能。研究成果对隔离墙的服役性能评价和科学设计都有重要意义。Vertical cutoff wall is one of the most effective technologies to restrict the migration of contaminants and has been widely used for in-situ management and control of contaminated soil and groundwater.The traditional cutoff wall materials are highly susceptible to performance degradation under dry-wet cycles,leading to a significant reduction in service life.Through a series of macroscopic and microscopic experiments,the influences of sodium bentonite,magnesium oxide,and microcapsules on the evolution of permeability characteristics and microstructure of fly ash-based geopolymer cutoff wall materials under dry-wet cycles were investigated.The results showed that the unconfined compressive strength(UCS)and permeability coefficient of different geopolymer cutoff wall materials all met the anti-seepage design requirements for cement-based cutoff walls,achieving 6.62 MPa and 4.73×10^(-11) m/s,respectively,after being cured for 28 days.The permeability coefficient of samples without modified materials exceeded 1×10^(-8) m/s after the first dry-wet cycle,while that of samples with modified materials could still meet the design requirements after five cycles.The three modified materials can effectively influence the proportions of micropores(<0.05μm),mesopores[0.05μm,0.10μm],and macropores(>0.10μm),thereby improving the anti-seepage performance of geopolymer cutoff wall materials under dry-wet cycles.This study has significant implications for the performance evaluation and scientific design of cutoff walls.

关 键 词：隔离墙 干湿循环 地聚物 渗透特性 微观机制 

分 类 号：TU443[建筑科学—岩土工程]