海河交汇区水泥搅拌桩加固技术初探  

A preliminary study on the soil improvement technology with deep cement mixing method in the intersectional region between the sea and river

作　　者：杨文军 吴毅航 门小雄 郭保和 刘辉 戴北冰 刘建坤 YANG Wen-jun;WU Yi-hang;MEN Xiao-xiong;GUO Bao-he;LIU Hui;DAI Bei-bing;LIU Jian-kun(China Railway Tunnel Group Co.,Ltd.,Guangzhou 511458,Guangdong,China;School of Civil Engineering,Sun Yat-sen University,Guangzhou 510275,Guangdong,China;Zhuhai Rail Transit Co.,Ltd.,Zhuhai 519100,Guangdong,China;Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai),Zhuhai 519082,Guangdong,China)

机构地区：[1]中铁隧道局集团有限公司,广东广州511458 [2]中山大学土木工程学院,广东广州510275 [3]珠海市轨道交通有限公司,广东珠海519100 [4]南方海洋科学与工程广东省实验室(珠海),广东珠海519082

出　　处：《地基处理》2024年第2期162-171,共10页Journal of Ground Improvement

基　　金：国家自然科学基金(52078507)。

摘　　要：本文依托珠海隧道工程,针对超深欠固结淤泥地层,进行一系列不同配比、施工工艺、水灰比和QC-固化剂比例条件下的水泥搅拌桩加固试桩试验,系统研究了多种参数影响下辅道、明挖基坑和海域浅覆土加固试桩的成桩效果,发现掺入固化剂可获得更好的成桩效果和更优良的抗压性能。经加固处理的芯样其强度大部分在1~3 MPa,部分芯样强度可高达5 MPa,且桩身更为连续和完整。在其他参数相同的条件下,QC-固化剂占比高的芯样具有更好的完整性和强度,而水灰比对成桩效果及抗压强度的影响不大,四搅和两搅的施工工艺在单点土体切削次数达到20次或以上时,其对成桩效果和强度的影响无明显区别。最后对加固后的软土开展了微观电镜扫描试验,对比分析了经QC-固化剂与纯水泥固化剂加固后生成晶体对土体孔隙的填充现象,发现QC-固化剂对土体孔隙具有更好的填充效果。本水泥搅拌桩加固试桩试验在珠海海河交汇区软弱地层取得了较好的加固效果,可为沿海地区类似地质条件下的地基处理提供参考。The soil improvement technology involving deep cement mixing method is implemented in the intersectional region of sea and river in Zhuhai,where a tunnel project is situated.Field tests were conducted on the under-consolidated sludge layer with considerable depth.The tests considered the compounding ratio,construction technique,water-cement ratio,and QC-curing agent ratio.It was found that the addition of curing agent leads to a better pile formation pattern and compressive strength.After treatment,the compressive strength of most core samples falls within the range of 1-3 MPa,reaching as high as 5 MPa for some core samples.Additionally,the pile tends to be continuous and intact.Under comparable conditions,core samples treated with a higher QC-curing agent material exhibit increased completeness and strength.The water-cement ratio does not significantly impact the pile formation pattern and compressive strength.The influence of the construction techniques of four-stirring and double-stirring on the pile formation pattern and strength is not markedly different when the soil cutting times reach or exceed 20 at a single point.Finally,the scanning electronic microscope pictures were captured for treated soft soil,comparing the filling effects of crystals produced by the QC-curing agent and pure cement agent on the soil pores.The QC-curing agent demonstrated a superior filling effect on the soil pores.The deep cement mixing pile test conducted in this work has successfully treated the soft soil in the intersectional region between the sea and river in Zhuhai.The results obtained in this work are expected to offer valuable guidance and references for improving soft soil under similar geological conditions in coastal areas.

关 键 词：试桩 加固 淤泥层 固化剂 水泥搅拌桩 软土 隧道 

分 类 号：TU472[建筑科学—结构工程]