摘要
采用pH=6的富里酸(fulvic acid,简称FA)溶液模拟泥炭土腐殖酸弱酸地下水环境,并用于浸泡由普通硅酸盐水泥(ordinary Portland cement,简称OPC)所固化的含腐殖酸软土,通过表观现象、微观电镜、烧失及渗压等试验探究此环境对含腐殖酸水泥土结构及渗透性的影响机制。结果表明:FA会与水泥水化产物及水化所释放的多价金属阳离子发生络合反应并生成有机金属胶体,此过程会消耗水化产物、抑制水化进程;OPC掺量较少时,生成的有机金属胶体不足且会发生迁移,导致试样表层软化脱落。内部结构受胡敏酸(humic acid,简称HA)与FA的影响而呈团粒或团块连接,大孔隙较多,渗透系数k较大,且随浸泡龄期的增加愈加显著;提高OPC掺量不仅能抑制FA的渗入、促进有机金属胶体沉积于试样表层形成致密层,还能加强试样内部水化产物的连结与填充作用,使试样完整性提高、孔隙数量减少、k减小;兼顾工程安全及绿色低碳需求,采用OPC固化含腐殖酸软土时,其掺量宜介于23.3%与30.0%之间。
This study used a fulvic acid(FA)solution with a pH of 6 to simulate the weakly acidic groundwater environment typically caused by humic acid in peat soil.The FA solution soaked soft soil containing humic acid that had been solidified with ordinary Portland cement(OPC).Various methods,including visual observation,microscopic analysis,loss on ignition testing,and osmotic pressure tests,were employed to investigate how this environment influenced the structure and permeability of the humic acid-containing soil-cement.The results indicate that FA undergoes complexation reactions with cement hydration products and polyvalent metal cations released during hydration,leading to the formation of organic metal colloids.This process depletes the hydration products and inhibits further hydration.When the OPC content is low,the quantity of organic metal colloids formed is insufficient,which may cause migration and result in the softening and detachment of the surface soil from the specimens.Additionally,the internal structure of the specimens,influenced by humic acid(HA)and FA,develops granular or blocky interconnected structures with numerous large pores.These changes increase the permeability coefficient(k)of the specimens,with the effect becoming more pronounced with extended immersion.Increasing the OPC content inhibits FA infiltration into the specimen and promotes the deposition of organic metal colloids on the surface,resulting in a dense surface layer.Higher OPC content enhances the bonding of hydration products to soil particles and improves pore filling,increasing the overall integrity.This reduces the number of pores and consequently lowers the k of the specimens.To balance engineering safety with environmental and low-carbon requirements,the OPC content used to solidify humic acid-containing soft soil should be controlled between 23.3%and 30.0%.
作者
张兴文
曹净
雷舒羽
李育红
程芸
张柠锐
ZHANG Xing-wen;CAO Jing;LEI Shu-yu;LI Yu-hong;CHENG Yun;ZHANG Ning-rui(School of Civil Engineering and Architecture,Kunming University of Science and Technology,Kunming,Yunnan 650500,China;YICH NO.1 Engineering Survey and Design Co.,Ltd.,Kunming,Yunnan 650033,China)
出处
《岩土力学》
北大核心
2025年第S1期249-261,共13页
Rock and Soil Mechanics
基金
国家自然科学基金(No.41967035)
关键词
富里酸环境
含腐殖酸水泥土
络合反应
有机金属胶体
微观结构
渗透系数
fulvic acid environment
humic acid-containing soil-cement
complexation reaction
organic metal colloid
microstructure
permeability coefficient
作者简介
第一作者:张兴文,男,1998年生,硕士研究生,主要从事环境岩土方面的研究。E-mail:20222110026@stu.kust.edu.cn;通讯作者:曹净,男,1966年生,博士,教授,主要从事环境岩土方面的研究。E-mail:20040310@kust.edu.cn
