山区航道跨河桥梁通航净空尺度研究

Research on navigable clearance dimensions of river-crossing bridge on mountainous waterway

我国内河高等级航道普遍存在大量现有桥梁通航净空不足的问题,如何科学合理地确定分步改造标准,是高等级航道建设中亟待破解的普遍性、关键性技术问题。以广东省北江、东江航道为例,对现有跨河桥梁净空尺度进行复核计算,结合代表船型预测提出船舶航行对桥梁的净空尺度要求,并对航道设计最高通航水位洪水标准的适应性进行分析。研究提出在北江、东江千吨级航道建设中,桥梁净空尺度满足净高不小于8.3 m(最高通航水位的洪水重现期2 a)、双向通航孔净宽不小于86 m或单向通航孔净宽不小于44 m的跨河桥梁可暂缓改建。在此基础上,综合考虑其他航道建设经验,提出适应国内千吨级山区航道桥梁改建标准的建议,研究结论可为内河高等级航道建设提供借鉴。

A large number of existing bridges have insufficient navigation clearance in China’s high-grade inland waterways.How to scientifically and rationally determine the standard of step-by-step reconstruction is a universal and key technical problem to be solved urgently in the construction of the high-grade waterway.Taking the Beijiang and Dongjiang waterway in Guangdong province as examples,we analyze the clearance dimension of the existing bridges in the study area.Combining with the prediction of representative ship types,we put forward the requirement of bridge clearance dimension for ship navigation and analyze the adaptability of the flood standard of the designed maximum navigable water level.It is recommended that the clearance dimension of the bridge should meet the requirements of 8.3 m clear height(the flood recurrence period of the design maximum navigable water level is 2 years),and 86 m clear width of two-way navigation with single holes,or 44 m clear width of one-way navigation with double holes in the Beijiang and Dongjiang kiloton waterway projects.On this basis,taking into account the experience of other waterway constructions,suggestions are put forward to adapt to the reconstruction standard of the kiloton mountain waterway bridge.The conclusion may serve as a reference for the construction of the high-grade inland waterway.