邻近既有桥梁的海域大面积筑岛填砂施工技术

Construction technology of large-area island construction andsand filling in sea adjacent to existing bridges

针对临近既有桥梁结构的大面积填砂施工存在的效率低、控制变形难等问题,结合深中通道东人工岛工程,基于数值模拟确定了桥下填筑顺序及方法,阐述回填筑岛关键施工技术,并通过监测数据、拱淤扫测验证施工效果。结果表明,“桩内-砂被-横桥向左/右交替”回填原则结合分砂器等装置可将既有桥梁变形控制在±5 mm内,降低66.7%的拱淤量;堆载反压、反方向卸载的变形纠偏效果显著;回填砂工程量须重点考虑回填料密实、含泥量、岛壁滤层流失等因素,本工程试验段回填砂流失率为4.21%。

In view of the problems of low efficiency and difficult deformation control in the construction of large-area sand filling near the existing bridge structure,combined with the east artificial island project of Shenzhen-Zhongshan Link,this paper determines the sequence and method of filling under the bridge based on numerical simulation,explains the key construction techniques of backfilling island construction,and verifies the construction effect by monitoring data and arch silt sweeping.The results show that the backfilling principle of“pile-sand quilt-cross-bridge left right alternating”,combined with sand splitter and other devices can control the deformation of the existing bridge within±5 mm and reduce 66.7%of arch siltation.The deformation correction effect of pile back pressure and unloading in the opposite direction is significant.The backfill sand volume needs to focus on the backfill density,mud content,and the loss of the filter layer of the island wall.The backfill sand loss rate in the test section of this project is 4.21%.