水下桥梁桩基础新型压入钢套箱加固技术

New Press-into Steel Casing Reinforcement Technique of Underwater Bridge Pile Foundation

桥梁桩基长期受河水的冲刷,经常会出现很多的病害,如蜂窝孔洞、钢筋外露等,直接影响桥梁结构的承载能力和使用安全。针对某特大桥的桩基长期受潮水起落的冲刷,部分桩基病害严重的问题,提出新型压入钢套箱加固桩基技术。此技术集自反力体系与吊装设备于一体,利用静力压入技术,将节段焊接拼装的加固钢管沿桥墩、桩基础四周压入土中,形成四周围堰,将钢管与桥墩、桩基础间隙间的水抽去之后,灌注快凝混凝土对桥墩、桩基础实现加固,给出了加固的关键施工工艺,加固后桩基表面混凝土光滑,无孔洞、大面积蜂窝麻面现象,病害治理效果明显。

Bridge pile foundation often suffers a lot of diseases such as honeycomb holes,exposed rebar,etc.when it is scoured by river water for a long time,which will directly influence the bearing capacity and service safety of bridge structure.A new press-into steel casing reinforcement technique is proposed for the partial pile foundations with the serious disease because of the pile foundations of a bridge scoured by the ebb and flow of the tide for a long time.This technique integrates the counter-force system and hoisting equipment.The static press-into technique is adopted to press the reinforced steel pipe of the segmental welding assembly into the soil along the surrounding of pier and pile foundation in order to form the surrounding cofferdam.After pumping the water out of the intervals among the steel pipe,pier and pile foundation,the fast-setting concrete is poured into the pier and pile foundation to realize the reinforcement.The key construction technologies of the reinforcement are given.The concrete surface of the reinforced pile foundation is smooth without the holes and the large-area voids and pits.The disease situation is obviously improved.