丹江口水库特大桥地锚式桥台施工关键技术  

Key Construction Techniques for Anchorage-Type Abutment of Danjiangkou Reservoir Bridge

作　　者：周范武 于得安 高海涛 ZHOU Fanwu;YU Dean;GAO Haitao(CCCC Second Harbour Engineering Co.,Ltd.,Wuhan 430040,China)

机构地区：[1]中交第二航务工程局有限公司,湖北武汉430040

出　　处：《桥梁建设》2023年第5期131-137,共7页Bridge Construction

基　　金：湖北省交通运输厅科技项目(2020-2-2-1)。

摘　　要：丹江口水库特大桥为主跨760 m双塔双索面部分地锚式混合梁斜拉桥,边中跨比为0.2,采用“梁塔分离、梁台固结”的结构体系,在边跨主梁端部设置地锚式桥台作为配重。地锚式桥台采用空腔式箱形台身+岩锚的组合式结构,由底板、墙身(包括前墙、后墙、侧墙、隔墙)、盖板和锚台段主梁构成,桥台长45.8 m、宽31.6 m。在地锚式桥台施工中,基坑采用明挖放坡方式开挖,并在开挖后对基底进行浅层平板荷载试验,以确保其地基承载力满足不小于350 kPa设计要求;底板采用分层分块方式施工,并设置2条横向后浇带和智能管冷循环控制系统;墙身采用竖向分层+设置双向后浇带(2条横向后浇带、1条纵向后浇带)的方式施工,并根据分块龄期差采用微膨胀混凝土施工后浇带;墙身施工后,采用传送带在墙身腔室内回填砂石,之后进行盖板与锚台段主梁施工;最后进行地锚式桥台竖向预应力施工,并优化竖向预应力张拉顺序,完成地锚式桥台施工。The Danjiangkou Reservoir Bridge is a two-pylon hybrid girder cable-stayed bridge with a main span of 760 m.The stay cables are arranged in double cable planes,where pairs of end cables are anchored in the anchorage-type abutments to create a partially earth-anchored structure.The side span to central span ratio reaches 0.2.The main girder and the pylons are not fixed,while the main girder and the abutments are fixed,and the anchorage-type abutments flanged the ends of the side spans also serve as counterweights.Measuring 45.8 m by 31.6 m,the anchorage-type abutment consists of a hollow box body and rock anchorages,specifically including the constituents of bottom slabs,walls(front,back,side walls and partitions),cap slabs and anchorage section.During the construction of the anchorage-type abutment,the foundation pit was excavated by the open cut slope excavation method.Upon the completion of excavation,a shallow plate load test was carried out to examine and ensure that the load bearing capacity of the pit bottom would be over the required value of 350 kPa.With an intelligent pipe cooling system,the bottom was cast in layers and zone by zone,leaving two transverse post-pour strips.The walls of the foundation were cast vertically layer by layer,leaving two transverse post-pour strips and one longitudinal post-pour strip.The post-pour strips were filled with micro-expansion concrete,following a sequence considering the age difference of the surrounding concrete.After the construction of foundation walls,cavities were backfilled with sand and gravels delivered by a conveyor.Afterwards,the cap slabs and anchorage section were cast.At last,the vertical prestressing tendons in the anchorage-type abutment was installed and tensioned with an optimized sequence.

关 键 词：部分地锚式斜拉桥 地锚式桥台 基坑开挖 双向后浇带 腔室回填 施工技术 

分 类 号：U448.27[建筑科学—桥梁与隧道工程] U443.21[交通运输工程—道路与铁道工程] U445.4