地铁线路穿越双跨现浇混凝土异形板式梁桥的拆除施工技术

Demolition construction technology of crossing double span cast-in-place concrete special-shaped slab girder bridge of metro line

福州轨道交通4号线岳~池区间与化工河相交,在盾构施工前,将化工河桥面拆除并将部分桩位拔除以避开区间后重建。化工河桥上部结构采用异形钢筋混凝土现浇板,按照道路轴线和桥墩轴线,将桥梁板划分为4个作业区,每个作业区的梁板为近似梯形,单块板重约600t,对每个梁板分别切割成小块后外运。对于需要拆除的桥梁桩基础采用原位冲钻法,使用冲击钻机在桩基处冲钻成孔,利用循环泥浆带出碎渣。通过合理使用桥梁的拆除工艺,特别是对现浇异形梁板采用分块拆除吊运,不仅省去了水中搭设满堂支架所造成的行洪隐患,也大大加速了施工进度。

Before the shield construction,the Huagong River Bridge will be demolished and some piles will be pulled out to avoid the section for reconstruction.The uperstructure of Huagong River bridge adopts special-shaped reinforced concrete cast-in-place slab.According to the road axis and pier axis,the bridge slab is divided into four operation areas.The beam and slab in each operation area is approximately trapezoidal,and the single slab weighs about 600t.Each beam and slab is cut into small pieces and then transported out.For the bridge pile foundation which needs to be demolished,the in-situ drilling method is adopted.The percussion drill is used to drill holes at the pile foundation,and the circulating mud is used to carry out the crushed slag.Through the reasonable use of bridge demolition technology,especially for the cast-in-place special-shaped beam and slab,the hidden danger of flood discharge caused by setting up full support in water is not only saved,but also the construction progress is greatly accelerated.