高速公路无铰拱天桥爆破拆除

为了沈海高速公路开平至阳江段K110+254无铰拱钢筋混凝土(C30混凝土)跨线天桥顺利爆破拆除,针对该天桥为中承式等截面悬链线无铰肋拱桥,净跨39 m,净高约6.83 m,桥面净宽10.2 m的结构特点,根据施工要求,采取拱圈钻孔爆破的原地坍塌方案。由于施工作业不能影响桥下高速公路的运营,因此在高速公路路面铺垫缓冲减振层,保护路面不受损坏;拱圈上共设置10个爆破切口,拱脚处爆破切口长3.8 m,其他切口长3.0～3.2 m,两侧桥台及立柱在不影响桥下高速公路通行的前提下使用机械破碎。采用计算机软件模拟切割后桥面和拱圈的受力情况,以选择合理的切割位置和合适的钻孔布置。对拱圈钻孔装药位置使用密目网和密竹栅栏进行爆破飞石近体防护,拱顶堆载沙包防护。使用多段毫秒延时导爆管雷管起爆网路,逐渐对称地形成爆破切口,确保桥体按预定的倾倒方向整体坍塌,由此实现了运营中高速公路的无铰拱天桥爆破拆除。

Blasting demolition of hingeless arch overpass bridge in expressway

The demolition blasting of reinforced hingeless arch concrete(C30 concrete) overpass bridge in the Kaiping-Yangjiang the K110+254 section of the Shenyang-Haikou expressway, the bridge is a mid-supported cross-section catenary without hinged rib arch bridge with a net span of 39 m, the net height is about 6.83 m, and the bridge deck has a net width of 10.2 m. According to the construction requirements, the in-situ collapse scheme of the arch ring blasting is adopted. Since the construction operation can not affect the operation of the expressway under the bridge, cushioning the vibration reduction layer on the highway pavement to protect the road surface from damage; 10 blasting incisions are set on the arch ring, and the blasting incisions at the arch are 3.8 m long, other incisions are 3.0-3.2 m long, the bridges and columns on both sides use mechanical crushing without affecting the passage of the expressway under the bridge. The computer software is used to simulate the force of the bridge deck and the arch ring after cutting to select a reasonable cutting position and a suitable drilling arrangement. For the drilling position of the arch ring, the dense mesh and the dense bamboo fence are used to carry out the near-body protection of the blasting flying stone, and the top of the arch is loaded with sandbag protection. The multi-segment millisecond delay detonator detonation network is used, and the blasting incision is gradually formed symmetrically to ensure that the bridge body collapses in a predetermined dumping direction, thereby realizing the blasting demolition of the hingeless arch bridge of the running highway.