摘要:研究目的:我国水系发达、河流众多。当铁路与大型通航河流交叉时，桥位选择受线路选线、接线条件、通航防洪、工程投资、施工、维养、社会效益等方面影响;桥型选择不仅要满足功能要求、技术标准，在技术、经 济指标、景观效果、施工组织等方面也要全盘考虑。本文结合蒙华铁路汉江特大桥桥位选择、桥型选择、主桥 设计等方面成果，重点研究大型跨河桥梁桥式方案的确定和重载铁路矮塔斜拉桥主桥设计。研究结论:通过对蒙华铁路汉江特大桥桥位的选择、桥式方案的确定以及主桥的设计，研究分析得出: 大型跨河桥梁的桥位由于受河道条件、通航要求、大型结构受力复杂等方面因素，相邻线位应服从桥位的 选择；（2)桥位的选择应结合防洪、通航要求、港口条件、水源特点、地方规划要求、相邻跨河建筑安全距离等 综合确定;（3)桥梁结构型式的选择必须在满足功能要求、技术标准的前提下，从技术、经济指标、施工组织、景观效果等方面综合比选；（4)重载铁路设计活载大、疲劳要求高，部分斜拉桥设计应重点关注对结构的强 度、疲劳及后期徐变等方面研究，蒙华铁路汉江特大桥矮塔斜拉桥是安全可靠的；（5)该研究成果可应用于铁 路大型 河桥 载铁路 桥 。

Abstract:Research purposes: Our country has well - developed river system and numerous rivers. When the railway crosses large navigable river，bridge site selection is influenced by route selection，connection condition，navigation and flood control，project investment，construction，maintenance，and social benefits; the selection of bridge types should not only meet the functional requirements and technical standards，but also should consider the technical and economic indexes，construction organization and landscape effects. Combined with the results of the bridge site and type selection， main bridge design of Hanjiang River super large bridge of Mengxi - Central China Railway，this paper focuses on bridge type scheme determination of large bridge and main bridge design of heavy haul railway low - pylon cable - stayed bridge. Research conclusions : Through the choice of bridge site，determination of bridge type scheme and the design of main bridge on the Hanjiang River Bridge of Mengxi - Central China Railway，the research results show that: (1) The bridge site of large bridge across the river bridge is influenced by channel conditions，navigation requirements，large complex structure stress and other factors，so the adjacent line should take from the bridge site selection. (2) The selection of bridge site should be combined With the adjacent flood control，navigation requirements，port conditions，water features， local planning requirements， river crossing construction safety distance. (3) The bridge type is comprehensively selected from the aspects of technology，economy， construction organization and landscape effect under the premise of meeting the functional requirements and technical standards. (4) The design of heavy haul railway should have large live load and high fatigue requirements $ and cable - stayed bridge design should focus on the research on the structure strength, fatigue and subsequent creep. It is safe and reliable for the low - pylon cable - stayed bridge of the Hanjiang River super large bridge of Mengxi - Central China Railway. (5 ) The research results can be applied to the design of large span bridge and the design of heavy haul railway cable - stayed bridge.