坝陵河大桥隧道锚锚塞体关键施工技术

Key Construction Technique for Anchor Plug in Tunnel Anchorage of Balinghe River Bridge

坝陵河大桥主桥为单跨双铰钢桁加劲梁悬索桥,西岸采用隧道式锚碇,其锚塞体竖向分14层施工。为解决定位架施工难度大及预应力管道施工精度要求高的难题,经方案分析比选,定位架采用先在锚洞外加工成杆件、在锚洞内分节拼装成型方案,预应力管道采用分段拼装方案。施工中控制定位架单根杆件最大重量小于55kg,预应力管道按6m一段安装在定位架上,同时重点控制槽口模板、锚垫板、定位板及预应力管道的定位。为解决高落差混凝土泵送难题,主要对其混凝土原材料进行控制,并布设"之"字形拖泵管等。为解决大体积混凝土温度控制难题,控制混凝土入模温度小于28℃;分14层浇注,且层间浇注间歇控制在7d左右;埋设冷却水管降低混凝土内、外温差。

The main bridge of the Balinghe River Bridge is a single-span double-hinged suspension bridge with steel truss stiffening girder. The main cables at the west bank of the river are anchored by tunnel anchorage, the anchor plug inside the anchorage is erected in 14 layers in vertical direction. Given that the positioning frame is difficult to erect and the installation of prestressed ducts has rigid precision demand, and based on the analysis of different schemes, it is suggested that the components of the positioning frame are fabricated outside the tunnel in ad vance and assembled in segments inside the tunnel, and the prestressed ducts are assembled section by section. The maximum weight of a single component of the positioning frame is controlled to be less than 55 kg in the construction process. The prestressed ducts are separated into sections of 6 m in length and installed on the positioning frame. And the positioning of the fillister formwork, anchoring pad, positioning plate and prestressed ducts was the key control point. To resolve the problem of the pumping of high drop concrete, the raw materials of the concrete were strictly controlled, and Z-shaped concrete pumps were arranged. For the temperature control of the large volumn concrete, the temperature was controlled to be below 28℃ when the concrete was taking into the pump; the concrete was cast in 14 layers and the intervening time between two layers was around 7 days, moreover, the cooling water pipes were buried to decrease the in- ternal-external temperature difference of the concrete.