摘要
针对江阴第二过江通道工程中泥水盾构产生的高含水率超高黏粒含量废弃泥浆泥水分离困难、处理效率低的问题,采用阴离子型聚丙烯酰胺(APAM)、聚合氯化铝(PAC)和聚合氯化铝铁(PAFC)3种絮凝剂开展泥浆絮凝试验,研究不同絮凝剂的絮凝脱水效果,选取底泥等效含水率、界面沉降速率、上清液浊度、泥浆脱水率以及Zeta电位作为评价指标,分析絮凝剂类型、用量、复配形式等对絮凝效果的影响,并探讨不同絮凝剂的絮凝机制。试验结果表明:1)不同絮凝剂对应的泥浆脱水效果排序为APAM>PAFC+APAM≥PAC+APAM>PAFC≥PAC,上清液浊度去除效果排序为PAFC>PAC>PAFC+APAM>PAC+APAM>APAM;2)有机絮凝剂APAM的最适投加量与其分子量密切相关,且不同分子量APAM的极限脱水率不尽相同,药剂分子量保持在1200万~1400万时,脱水效果最佳;3)PAFC+APAM复配絮凝剂对本依托工程中高含水率超高黏粒含量废弃泥浆调理效果最好,PAFC溶液和APAM溶液的最适投加量分别为33 g·L^(-1)和233 g·L^(-1),对应的PAFC和APAM干物质投加量分别为1.6 g·L^(-1)和0.466 g·L^(-1),在此条件下,泥浆90 min脱水率为29.6%,上清液浊度可降低至62.0 NTU;4)复配絮凝剂的脱水效果主要由有机絮凝剂APAM长链的吸附架桥作用主导,对上清液浊度的去除主要与无机絮凝剂PAC和PAFC的电性中和作用相关。
A significant volume of waste slurry with high water content and ultra-high clay particle content is produced during slurry shield tunneling in the second Jiangyin cross-river tunnel project.The water and slurry are hard to separate,resulting in low separation efficiency.Hence,various flocculants are used for slurry flocculation experiments to investigate the effect on flocculation and dehydration.The equivalent water content of sediment as well as interface sedimentation rate,supernatant turbidity,slurry dehydration rate,and Zeta potential are selected as evaluation indices to study the influence of flocculant type,dosage,and composite form on its flocculation effect.Finally,the flocculation mechanism of different substances is preliminarily discussed.The results reveal the following:(1)The slurry dehydration effect of different flocculants is in the following order:APAM>PAFC+APAM≥PAC+APAM>PAFC≥PAC,whereas the order of turbidity removal effect is as follows:PAFC>PAC>PAFC+APAM>PAC+APAM>APAM.(2)The optimal dosage of organic flocculant APAM is closely related to its molecular weight,and the maximum rate of dehydration varies for APAMs with different molecular weights.The best dehydration effect is achieved when the molecular weight of the agent is maintained at 12-14 million.(3)The PAFC+APAM composite flocculant exhibits the best conditioning effect on the waste slurry with high water content and ultra-high clay particle content.In this research,the optimal dosages for PAFC and APAM solutions are 33 and 233 g·L^(-1),respectively,and the corresponding dosages of dry matter for PAFC and APAM are 1.6 and 0.466 g·L^(-1),respectively.Under this condition,the dehydration rate of the slurry is 29.6%after 90 min,and the turbidity of the supernatant can be reduced to 62.0 NTU.(4)The primary mechanism responsible for the dehydration effect of composite flocculants is the adsorption bridging effect of the long chain of the organic flocculant APAM.Meanwhile,turbidity removal is mostly associated with the electrical neutr
作者
豆留盼
王峻
李海涛
吴东阳
张心源
魏力峰
DOU Liupan;WANG Jun;LI Haitao;WU Dongyang;ZHANG Xinyuan;WEI Lifeng(Key Laboratory of Transportation Tunnel Engineering,the Ministry of Education,Southwest Jiaotong University,Chengdu 610031,Sichuan,China;Jiangsu Province Transportation Engineering Construction Bureau,Nanjing 210004,Jiangsu,China)
出处
《隧道建设（中英文）》
CSCD
北大核心
2024年第4期771-782,共12页
Tunnel Construction
基金
国家自然科学基金(52078428)
四川省杰出青年基金项目(2020JDJQ0032)。
关键词
泥水盾构
絮凝
废弃泥浆
超高黏粒含量
高含水率
脱水性能
slurry shield
flocculation
waste slurry
ultra-high clay particle content
high water content
dehydration performance
