南京长江第四大桥南锚碇基础地下连续墙施工  

Construction of Underground Diaphragm Wall for South Anchorage Foundation of the 4th Nanjing Changjiang River Bridge

作　　者：杨奉举[1] 牛小龙[1] 

机构地区：[1]中铁大桥勘测设计院有限公司,湖北武汉430050

出　　处：《桥梁建设》2010年第6期77-79,83,共4页Bridge Construction

摘　　要：南京长江第四大桥主桥为双塔三跨悬索桥,其南锚碇基础支护结构为"∞"形地下连续墙,分Ⅰ期、Ⅱ期2种槽段,槽段采用铣接法连接。施工前先进行地质水文详勘与封排水设计、地基加固、修筑导墙及试验槽段施工。按隔墙、北外墙、Y形槽段、南外墙顺序施工地下连续墙,先施工Ⅰ期槽段,再施工Ⅱ期槽段。Ⅰ期槽段采用三铣成槽,Ⅱ期槽段采用一铣成槽,Y形槽段采用五铣成槽。在外墙预埋钢管进行墙底帷幕灌浆。基坑开挖前进行抽水试验,结果表明基坑日渗水量≤150 m3;基坑开挖过程中,围护结构变形和周边土体的沉降均小于预警值,说明地下连续墙施工质量良好。The main bridge of the 4th Nanjing Changjiang River Bridge is a two-tower and three-span suspension bridge. The lagging structure for the south anchorage foundation pit of the bridge is of the ＂∞＂-shape underground diaphragm wall that has two types of Phase Ⅰ and PhaseⅡ trough sections connected by the milling connection method. Before the construction of the diaphragm wall started, the detailed survey of hydrology and geology, the design of water stoppage and drainage and the construction of ground reinforcement, guiding walls and trial trough sections were carried out. The diaphragm wall was then constructed in the sequence of firstly the Phase I trough section and late the Phase Ⅱ trough section form the partition walls to the north outer walls, Y-shape trough section and south outer walls. The Phase I trough section was completed by three times of milling, the Phase Ⅱ trough section by one time of milling while the Y- shape trough section by five times of milling. The steel pipes were embedded in the outer walls to be used for curtain grouting to the wall bases. Before the foundation pit was excavated, the water pumping tests were made and it was known from the tests that the daily water seeping in the pit was 4150 m^3. In the process of the pit excavation, the deformation of the lagging structure and the settlement of soil around the pit were all less than the precaution values, showing that the construction quality of the diaphragm wall was quite good.

关 键 词：南京长江第四大桥 悬索桥 基础 地下连续墙 帷幕灌浆 桥梁施工 

分 类 号：U448.25[建筑科学—桥梁与隧道工程] U445.55[交通运输工程—道路与铁道工程]