研究目的:黔张常铁路沿线地形地质条件极其复杂,可溶岩分布广泛,环保要求高,为降低岩溶区段工程建设的风险,采取了高线位的线路方案。本文通过系统总结复杂山区岩溶地质条件下桥梁工程特点,研究给出可溶岩区桥梁结构选型、岩溶区基础处理措施的原则,并分析总结两座矮塔斜拉桥技术特点,为同类桥梁提出经济合理的桥式方案选择。
研究结论:(1)岩溶山区铁路地质条件复杂,桥梁结构选型应以合理跨越、有效避让为原则;(2)溶洞的处理应视其分布特点采取不同的应对措施;(3)矮塔斜拉桥结构刚度大、动力特性优,斜拉索加劲可有效控制混凝土结构的徐变变形,可作为同类型特点铁路桥梁的首选;(4)本研究成果可为复杂山区、岩溶区铁路桥梁设计提供借鉴和参考。

Research purposes:The terrain and geological conditions along the Qianjiang-Zhangjiajie-Changde railway are extremely complex, the soluble rock is widely distributed, and the environmental protection requirements are high. In order to reduce the risk of the construction of karst section, a high line plan is adopted. This paper systematically summarizes the characteristics of bridge engineering under karst geological conditions in complex mountainous areas, studies and gives the principles of bridge structure selection and foundation treatment measures in karst areas, analyzes and summarizes the technical characteristics of two extradosed cable-stayed bridges, and puts forward an economic and reasonable bridge selection for similar bridges.
Research conclusions:(1) The geological conditions of railway in karst mountainous areas are complex, and the selection of bridge structure should be based on the principle of reasonable crossing and effective avoidance. (2) Different measures should be taken to deal with karst caves according to their distribution characteristics. (3) Extradosed cable-stayed bridge has large structural stiffness and excellent dynamic characteristics. Cable stiffening can effectively control the creep deformation of concrete structure, which can be used as the first choice for railway bridges with the same condition. (4) The research results can provide reference for railway bridge design in complex mountainous and karst areas.