超大型锚杆式悬索桥锚碇锚固系统施工关键技术

随着我国高速铁路等交通事业的不断发展,大型悬索桥不断涌现,其锚碇及其锚固系统向更大空间尺寸、更大受力方向迅速发展。针对主缆锚固系统的施工工艺,依托新建连镇铁路五峰长江特大桥建设实践,系统分析其结构特点及施工难点,发现常规锚固系统施工工艺先安装定位钢支架后浇筑混凝土的局限性,提出"V"形混凝土台阶+型钢混合型定位支架和逐层安装锚杆逐层跟进浇筑混凝土施工新工艺。采用常规及新工艺的南、北锚碇锚固系统施工对比表明,南锚碇定位支架结构最大变形量20 mm,北锚碇定位支架最大变形量2.43 mm,新工艺减小了支架变形87.8%;南、北锚碇锚固系统施工用时分别为402,261 d,新工艺提升效率35.1%;南、北锚碇锚固系统定位支架总用钢量分别为1 869,960 t,采用新工艺节约了48.6%的支架钢材。最后进一步讨论了施工工艺的优化建议。

Key Construction Technology of Super Large Anchor-bar Anchorage System for Suspension Bridge Anchorage

With the continuous development of China's high-speed railway and other transportation undertakings, large suspension bridges are constantly emerging, and their anchorage is developing rapidly in the direction of larger spatial size and larger force carrying capacity. Aiming at the construction technology of the main cable anchorage system and relying on the construction practice of the WufengshanYangtze River super large bridge on the newly-built Lianyungang-Zhenjiang railway, this paper analyzes structural characteristics and construction difficulties, identifies the limitations of the conventional construction technology by installing the positioning steel bracket of the anchorage system before concrete casting, and puts forward such new construction technologies as V-shaped concrete steps mixed with section steel positioning bracket and layer-by-layer concrete pouring. The comparison of the construction of the south and north anchorage systems using conventional and new technologies shows that the maximum deformation of the south anchorage positioning bracket structure is 20 mm, and that of the north anchorage positioning bracket structure is 2.43 mm. The new process reduces 87.8% of the deformation. The construction of the anchorage system of the south and north anchorage consumes 402, 261 days respectively, and the new process improves the efficiency by 35.1%. The total steel content of the positioning bracket of the south and north anchorage system are 1 869 t and 960 t respectively, and the new process saves 48.6% of the bracket steel. Finally, suggestions for construction process optimization are further discussed.