复杂环境下大型块石混凝土拱桥爆破拆除

Demolition Blasting of Large-stone Concrete Arch Bridge in Complex Environment

待拆除桥梁为块石混凝土拱桥,桥面宽23.5 m,桥梁全长198 m,周边存在多处民用建筑、医院以及军用雷达等,环境较为复杂。为保证大桥顺利拆除,设计采用“逐跨分段逐孔延时精确控制爆破技术”:利用“深孔浅孔相结合”的方式,在桥墩处钻凿垂直深孔,在拱脚以及拱顶处钻凿垂直浅孔,针对不同尺寸、材料的爆破部位选择不同的爆破参数,以此破坏大桥各跨的关键承重部位,同时使得大桥不同部位分批垮落,将爆破与塌落振动等有害效应控制在安全范围内;采用竹笆、悬挂以及毛竹帘对桥梁爆破部位进行防护,有效降低了飞石距离,确保了周边建(构)筑物的安全。

The bridge to be demolished is a stone concrete arch bridge.Its deck is 23.5 m wide and its total length is 198 m.There are many civil buildings,hospitals and military radars around the bridge.The environment is more complicated.In order to ensure the smooth demolition of the bridge,the"precision control blasting technology of span-by-span section and hole-by-hole delay"is adopted in the design.By using the method of"combining deep and shallow holes",the vertical deep holes are drilled at the piers,and the vertical shallow holes are drilled at the arch feet and vaults.Aiming at the different sizes and materials of blasting parts,the different blasting parameters are selected so as to destroy the key load-bearing parts of each span of the bridge,and at the same time,to make the different parts of the bridge collapse in batches.The harmful effects such as blasting and collapse vibration are controlled within a safe range.The bamboo basketry,hanging and moso bamboo curtain are used to protect the blasting parts of the bridge,which can effectively reduce the distance of the flying stone and ensures the safety of the surrounding buildings and structures.