景文高速高岭头水库特大桥设计方案研究

Study of Design Solutions for Gaolingtou Reservoir Bridge of Jingwen Expressway

景文高速高岭头水库特大桥跨越高岭头水库,地处V形峡谷,地形地质复杂,地面高差大、横坡陡直,施工场地狭窄,两侧接叶麻尖2号隧道、西坑互通。经综合比选,桥位采用对水库及周边环境影响小、顺应地形较顺直、路线长度最短、技术指标高、跨水库大桥的引桥高度小、对水库水流无影响的方案;结合桥位控制因素,对连续刚构桥方案、悬索桥方案和斜拉桥方案3种桥型方案进行比选,最终确定采用景观效果好、结构受力合理、造价适宜、技术成熟、施工难度及风险相对较低的主跨300 m斜拉桥方案。斜拉桥方案跨径布置为22×40 m+(140+300+140)m+6×40 m,主梁为预应力混凝土双肋板式梁,桥塔为钻石形桥塔。

The Gaolingtou Reservoir Bridge of Jingwen Expressway is located in a steep-sided ravine where the hydrogeological condition is complex.The bridge is expected to connect the Yemajian No.2 tunnel on one side and the Xikeng Interchange on the other side,which means big vertical distance from the deck to the base of the ravine and limited construction space.The bridge is required to bring minimum disturbance to the reservoir and surrounding environment,follow the local topography to have relatively straight alignment,be the shortest link between the accesses on the two sides,be designed and constructed with high technical standards,have low approaches and exert no disruption to the water flow in the reservoir.In this case,three types of bridges,including the continuous rigid-frame bridge,suspension bridge and cable-stayed bridge,were considered and compared,taking into the control factors at the bridge site.The solution of cable-stayed bridge with 300 m long main span was finally chosen by the integration of various factors,such as good aesthetic effect,rational load bearing behavior,economic construction costs as well as low technical challenge,construction complexity and safety risk.The cable-stayed bridge is arranged in spans of 22×40 m,140 m,300 m,140 m,and 6×40 m,with diamond-shaped pylons.The main girder consists of two prestressed concrete T beams and concrete slabs.