高山峡谷地区桥梁临时支架基础设计及吊装施工

On the Primary Design and Erecting Construction of the Temporary Support for Bridges in High-Mountain and Narrow-Valley Regions

以重庆龙潭互通式立交桥现浇梁施工为例,介绍了处于喀斯特地形的高山峡谷地区高支架现浇梁施工关键技术。地质环境差的高支架现浇梁施工,对地基基础要求高,安全风险大,物流组织复杂困难。针对施工过程中遇到的河道、陡坡、山洪及泥石流、场地狭小等地质环境问题,采用筑岛填筑、浇注挡土墙、设置排水沟、爆破开挖等多种方式形成施工平台,然后施作桩基础、扩大基础和条形基础保证了高支架的设置问题;综合采用汽车吊、塔吊组合的方式解决了施工材料吊运和支架吊装问题。实践证明,这些措施安全有效、科学合理,满足了工期要求,提高了经济效益。

With the casting-in-place construction of the inter-communication flyover at Longtan of Chongqing as a practical enginering example,introduced in the present paper are the key construction techniques for the tall cast-in-place supports in high-mountain and narrow-valley regions which are located in karst landform.The casting-in-place construction of tall supports in the poor geological environment is much demanding in foundation,high in safety risks,and difficult and complex in the organization of logistics.Aiming at solving the problems of river courses,steep slopes,mountainous floods,mud-rock flow,and the difficulties of the narrowness of the site and other geological and environmental factors,we have the island-building filling performed,retaining walls cast,draining ditches provided,and the blasting-digging and many other forms adopted to help establish the construction platform for the project,after which the pile foundation is built,the foundation is expanded,and the bar-type foundation is built to ensure the provision of the tall supports.The comprehensive use of the auto cranes in combination with the tower cranes helps solve the problems in transporting and lifting construction materials,and the erection of the supports.Practice shows that those measures adopted for the project are reliable,effective,scientific and rational,and they also help meet the requirement in construction duration with economic benefits improved.