2016年12月下
第45娄
酬忆集
DOI:10.7672/sgjs2016240021
施工技术
CONSTRUCTION TECHNOLOCY
江津中渡长江大桥南锚碳沉井施工技术
黎人亮，翟跃，呙佳，余剑（中建六局桥梁有限公司，重庆402260）
【摘要】江津中渡长江大桥南岸重力式锚碗沉井位于建筑物集中区.沉井平面尺寸为58.3m×45.8m，下沉23.5m，需要穿越9-12m砂卵石层，为西南地区首个大型沉井，施工难度很大。经过精确模拟计算，沉井施工采用钻孔灌注防护桩的方式确保周边建筑物的安全，同时减小了并壁侧摩阻力，利用砂套与空气幕作为下沉辅助措施，最终沉井顺利下沉到位，同时创新地采用“挖掘机+门式起重机+履带式起重机“组合机械出土方式，提高了施工效率。
通过实时监测并及时调整的技术确保了沉并下沉的平稳进行。【关键词】桥梁工程；悬索桥；锚碳；沉井；防护桩
【中图分类号】U445.55*7
【文献标识码］A
【文章编号】1002-8498(2016)24-0021-03
Construction Technology of South Anchorage Caisson of
Jiangjin Zhongdu YangtzeRiver Bridge
Li Renliang,Zhai Yue,Guo Jia,Yu Jian
(China Construction Sixth Engineering Dirision Bridge Co., Lid., Chongging402260, China)
Abstract: The gravity anchorage caisson of the south entrance of Jiangjin Zhongdu Yangtze River Bridge is located in a dense building area, covering a plane area of 58. 3m × 45. 8m with a sinking depth of 23. 5m. It needs to run through the sand and gravel stratum of 9 ~ 12m in depth. It is the first large-sized caisson in the southwest region of China and the construction is difficult. During the construction of the caisson, accurate simulation computation was adopted and protective cast-in-situ bored piles were employed to ensure the safety of surrounding buildings and reduce the side friction on the caisson walls. Abrasive sleeves and air screens were taken as the auxiliary sinking measures to make the caisson sunk in place. Meanwhile, the machinery combination of excavator and gantry crane and crawler crane was innovatively adopted in the excavation works, the construction efficiency was improved. The smooth
sinking of the caisson was guaranteed by real-time monitoring and timely adjustment. Key words:bridges;suspension bridges; anchorage; caisson; protective pile
1工程概况
重庆市江津中渡长江大桥主桥为主跨600m的双索面悬索桥，桥跨布置为（50+600+65）m，桥面宽33m，双向六车道，主跨加劲梁采用扁平形钢箱梁，梁高3.0m，桥塔采用门式框架结构，南岸采用重力式锚锭（见图1），北岸采用隧道式锚锭。
江津中渡长江大桥南锚醍沉井是西南地区最大规模的沉井。沉井长58.3m，宽45.8m，高 23.5m，共分25个井孔。沉井共分为4节，第1节为钢壳混凝土沉井，高6.0m；第2~4节均为钢筋混凝
*中建股份科技研发课题（CSCEC-2012-Z-22）
[作者简介】繁人亮，助理工程师，E-mail；278483270@qq.com
【收稿日期】2016-10-15 万方数据
土沉井，高5.5~6.0m，沉井封底混凝土厚8.0m。 2施工难点
21
首先，南铺啶沉井基础位于建筑物集中区，距离建筑物最近处约20m，沉井下沉施工过程中控制周围地基沉降量，确保周围建筑物的结构安全是沉井施工的难点。其次，沉井处地质不均匀，下沉过程中需穿越砂卵石层9~12m，在国内为首次，砂卵石粒径大，粒径>10cm的占50%~60%，砂卵石层侧摩阻力大，目前尚无实测的侧摩阻力值，西南地区尚无类似沉井下沉施工经验，沉井能否顺利下沉
到位是又一大难点。 3总体施工方案策划
针对工程施工难点，沉井下沉施工必须采取辅助措施，对沉井下沉全过程模拟计算，需要在沉井