Influence of ultrafine cement on cement-soil in peat soil environment of Dianchi Lake  

超细水泥对泥炭土环境下水泥土影响分析

作　　者：CAO Jing SUN Huafeng HUANG Siyang KONG Cheng LIU Fangyi LIU Fuhua TIAN Lin ZHU Weiming 曹净;孙华峰;黄思洋;孔程;刘方毅;刘富华;田林;朱伟明(昆明理工大学建筑工程学院,昆明650500;中国电建集团昆明勘测设计研究院有限公司,昆明650500;浙江万凝科技有限公司,杭州310000)

机构地区：[1]Faculty of Civil Engineering and Mechanics,Kunming University of Science and Technology,Kunming 650500,P.R.China [2]China Power Construction Group Kunming Survey Design&Research Institute Co.,Ltd,Kunming 650500,P.R.China [3]Zhejiang Wanning Technology Co.,Ltd,Hangzhou 310000,P.R.China

出　　处：《土木与环境工程学报(中英文)》2025年第2期1-12,共12页Journal of Civil and Environmental Engineering

基　　金：National Natural Science Foundation of China(No.41967035)。

摘　　要：Treatment of peat soil foundation in Yunnan surrounding Dianchi and Erhai Lakes poses complex problems for engineering projects.It is insufficient to rely on ordinary cement to reinforce peat soil.In order to make the reinforcement reliable,this experiment mixed(ultrafine cement)UFC into ordinary cement to form a composite solidify agent.This study aimed to analyze the influence of UFC proportion on the strength of cement-soil in the peat soil environment.Unconfined compressive strength(UCS)and scanning electron microscope(SEM)tests were conducted on samples soaked for 28 and 90 days,respectively.The test results show that without considering the effects of Humic Acid(HA)and Fulvic Acid(FA),incorporating UFC can significantly improve the UCS of cement-soil.The rapid hydration of the fine particles generates a large number of cementitious products,improves the cohesion of the soil skeleton,and fills the pores.However,when the proportion of UFC increases,the aggregate structure formed by a larger quantity of fine particles reduces the hydration rate and degree of cement hydration,making the UCS growth rate of cement-soil insignificant.In the peat soil environment,HA significantly weakened the UCS of cement-soil in both physical and chemical aspects.However,UFC can mitigate the adverse effect of HA on cement-soil by its small particle size,high surface energy,and solid binding ability.In addition,FA has a positive effect on the UCS of cement-soil soaked for 28 days and 90 days.The UFC addition could promote the enhancement effect of FA on cement-soil UCS.SEM test results showed that cement hydration products increased significantly with the increase of UFC proportion,and cementation between hydration products and soil particles was enhanced.The size and connectivity of cement-soil pores were significantly reduced,thereby improving cement-soil structural integrity.在云南环滇池、洱海地区,泥炭土地基的处理是实际工程项目的难题,仅依靠普通水泥加固泥炭土已不能满足要求。在有机质含量较低的冲洪积黏性土中掺入胡敏酸、水泥,并变化超细水泥(UFC)掺入占比,制备成水泥土试样。将试样浸泡在富里酸液中,以模拟泥炭土环境中的水泥土,通过对浸泡时间为28、90 d的水泥土试样进行无侧限抗压强度(UCS)试验和扫描电镜(SEM)试验,分析掺入UFC对泥炭土环境中水泥土强度的影响。结果表明:在不考虑胡敏酸和富里酸的影响时,掺入UFC可明显提高水泥土的UCS,其细颗粒快速水化,生成大量胶凝产物,提升了土体骨架的联结性并填充了孔隙;UFC掺入占比增加后,因细颗粒过多,形成的团聚体结构降低了水泥的水化速率和水化程度,进而使得水泥土的UCS增长率不明显;泥炭土环境下,胡敏酸在物理和化学方面都对水泥土的UCS产生了显著的削弱作用,而UFC凭借其粒径小、表面能高、结合能力强的特点,能适当削弱胡敏酸对水泥土造成的不利影响。此外,富里酸对浸泡时间为28、90 d的水泥土UCS具有一定的增强作用,而且添加UFC可适当促进富里酸对水泥土UCS的增强效果。扫描电镜(SEM)试验结果表明,随着UFC掺量的增加,水泥水化产物明显增多,水化产物和土颗粒间的胶结作用明显增强,水泥土孔隙的孔径显著减小,连通性显著降低,结构整体性增强。

关 键 词：peat soil environment ultrafine cement(UFC) cement-soil strength test MICROSTRUCTURE 

分 类 号：TU472.5[建筑科学—结构工程]