武汉杨泗港长江大桥主塔沉井硬塑黏土中下沉技术  

Techniques of Sinking Open Caissons for Towers of Wuhan Yangsigang Changjiang River Bridge in Hard Plastic Clay

作　　者：李陆平[1] 朱斌 罗瑞华[1] LI Lu-ping;ZHU Bin;LUO Rui-hua(China Railway Major Bridge Engineering Group Co.,Ltd.,Wuhan 430050,China;Wuhan Urban Construction Investment and Development Group Co.,Ltd.,Wuhan 430070,China)

机构地区：[1]中国中铁大桥局集团有限公司,湖北武汉430050 [2]武汉市城市建设投资开发集团有限公司,湖北武汉430070

出　　处：《桥梁建设》2018年第4期1-5,共5页Bridge Construction

摘　　要：武汉杨泗港长江大桥主桥为主跨1 700m的双层钢桁梁悬索桥,2个桥塔墩均采用沉井基础,沉井基底持力层均为硬塑黏土层,其中,1号和2号桥塔墩沉井需分别在硬塑黏土层中下沉6.2m和10.6m。2个桥塔墩沉井均采用不排水法下沉,当沉井刃脚进入硬塑黏土层后,井孔内的硬塑黏土采用绞吸法取土,先利用潜水挖泥机对土体进行强制式切削,再利用吸泥管将钻屑与水的混合物排出;刃脚下方的硬塑黏土采用水下爆破法取土,先将硬塑黏土炸松后抛掷到井孔内,再利用潜水挖泥机取出;沉井下沉时还采取了空气幕助沉技术。最终2个桥塔墩沉井基础在硬塑黏土中均顺利下沉到位。The main bridge of Wuhan Yangsigang Changjiang River Bridge is a double-deck steel truss girder suspension bridge with the main span of 1 700 m.The foundations for the 2 tower piers of the bridge are all the open caissons and the base bearing courses of the caissons are the hard plastic clay.In the construction of the caissons,the caissons for the tower piers No.1 and No.2 were required to respectively sink down 6.2 mand 10.6 min the clay.The caissons were sunk down,using the undraining method.At the time the cutting edges of the caissons were cutting into the clay,the clay in the well holes of the caissons was removed,using the reaming bit lifting method,that was,the dive dredger was firstly used to cut off the clay compulsorily and the mixture of the cuttings and water were then discharged through the air-lifting pipes.The clay underneath the cutting edges was removed,using the underwater blasting method,that was,the clay was firstly blasted loose and blasted to the well holes and was then removed,using the dive dredger.In the sinking of the caissons,the air curtain technique was also used to aid the sinking of the caissons and eventually,the 2 caissons were all smoothly sunk down in place in the clay.

关 键 词：悬索桥 沉井基础 硬塑黏土 潜水挖泥 空气幕 不排水下沉 施工技术 桥梁施工 

分 类 号：U448.25[建筑科学—桥梁与隧道工程] U445.4[交通运输工程—道路与铁道工程]