摘要
粉房湾长江大桥为主跨464 m的双塔双索面公铁两用斜拉桥,桥塔位于长江边的砂卵石透水地层中,为实现在汛期前完成基础施工、桥塔出水的目标,从施工工期、质量安全、经济性等方面对承台基坑的3种围堰方案(逆作混凝土围堰、浇筑封底混凝土方案;多级井点降水及简单支护方案;台阶法分级开挖及注浆止水帷幕施工方案)进行比选,最后选择采用台阶法分级开挖及注浆止水帷幕的施工方案,确定施工方案后,通过地层透水试验及注浆试验取得相关施工参数,确保基坑开挖施工成功实施。工程实践证明该方案具有止水效果显著、工程经济性高、省时的优点。
The Fenfangwan Changjiang River Bridge is a rail-cum-road cable-stayed bridge with double pylons,double cable planes and with a main span 464 m.The pylons of the bridge are located in the permeable stratum formed by sand and cobbles by the side of the river.To meet the target that the construction of the foundations could be completed and the construction of the pylons could be carried out above water level before the coming of flood periods,three cofferdam construction schemes for the foundation pits of pile caps of the pylons,including the reversely-constructed concrete cofferdam and concreting of cofferdam base sealing,the multi-level well-point dewatering and simple lagging and the multi-step excavation and water stoppage curtain grouting,were compared from aspects of the construction time schedule,quality,safety and economical efficiency.It was determined that the construction scheme of multi-step excavation and water stoppage curtain grouting should be selected and in accordance with the determined scheme,the corresponding construction parameters were obtained through a series of testing of the stratum water permeability and water stoppage curtain grouting to ensure that the excavation of the foundation pits could be successfully implemented.The construction practice proves that the scheme has advantages of significant water stoppage effect,good economical efficiency,and is time-saving.
出处
《世界桥梁》
北大核心
2011年第3期21-24,共4页
World Bridges
关键词
斜拉桥
基坑
施工
方案比选
注浆
止水帷幕
cable-stayed bridge
foundation pit
construction
scheme comparison and selection
grouting
water stoppage curtain
