岩溶地区中小跨径桥梁下部结构设计新思路

New Design Idea of Substructure of Medium and Small Span Bridges in Karst Area

岩溶地区桥梁桩基施工难度大、风险高、工期慢、造价高,对于中小跨径桥梁,甚至会出现桥梁桩基、溶洞处理的造价远高于桥梁上部结构的情况。针对此现象,结合清远市某景观桥的设计实例,取消其下部结构中的桩基,改为扩大基础,并通过一系列创新性的优化设计方式减小扩大基础的基底应力,使结构安全可靠。此方法避开了岩溶发育地区桩基的施工难度与风险,缩短了施工工期,节约了工程造价,为岩溶发育地区中小跨径桥梁下部结构的设计提供了一种新思路。

The construction of bridge pile foundation in karst area has the disadvantages of large difficulty,high risky,slow period and high cost.For the medium and small span bridges,there is a situation that the costs of bridge pile foundation and karst cave treatment are much higher than that of bridge superstructure.In view of this phenomenon,based on the design example of a landscape bridge in Qingyuan City,the pile foundation in its substructure is eliminated and the enlarged foundation is replaced.And the base stress of the enlarged foundation is reduced through a series of innovative optimization design methods to make the structure safe and reliable.This method avoids the construction difficulties and risks of pile foundation in karst area,shortens the construction period,saves the engineering cost,and provides a new idea for the design of substructure of medium and small span bridges in karst area.