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京广线黄河桥位于游荡性河段上,老桥“先天不足”,新桥受水利规划影响,基础提高,均属浅基。因而,养护人员一向重视该桥墩台的防护工作。 一、岸边防护 1963年秋末,主流偏北,北岸为石笼护岸,迫使水流回旋,发生坐弯顶冲,产生傍岸冲刷,造成新桥2~#墩冲刷14.8米,冲走石笼护岸200米及挑水坝片石护坡20米;冲毁下游顺水坝50余米,并在坝后形成二次小回流,威协路基安全。为使铁路安全运输,我们在2~#墩抛石笼553米~3,河岸边增打钢轨桩二排,同时在正线路基坡脚向上以干砌片石护坡。通过这次水毁事例,说明现有防护及调节设备,不能满足实际的要求。 二、墩台防护 1.矽化加固及消能潜桩 1968年铁道部科学研究院及郑州铁路局科研所于黄河大桥进行一组矽化试验,由于该河床为粉细砂,加之施工机具能力不适应,未能实际使用。尔后,铁科院根据1963年水毁实例,经过实地调查和模拟实验,认为。如果排除环流影响,就可能降低河底淘刷,排除环流的主要方法是顺直水流,而顺直水流最好的办法是在上游修建消能潜桩。通过试验,消能潜桩不仅有顺直水流的作用,而且在桩后还能促使泥沙回淤,填补墩台冲刷坑,根据铁科院建议,我们首次在黄河上采用消能潜桩对墩台进行防护。同时我们认为:由于黄河主槽流荡,河中有草滩、串沟等影响,在河道中部亦能引起集中冲刷。因而,在考虑变迁性河床冲刷时,应全面分析研究,不应只局限两岸。 2.抛石笼及预抛片石笼
The Beijing-Guangzhou line Yellow River Bridge is located in the wandering reach, the old bridge “congenitally inadequate”, Xinqiao affected by the water conservancy planning, improve the foundation, are shallow base. Therefore, conservation workers have always attached importance to the bridge piers protection work. First, the shore protection In the late autumn of 1963, the mainstream of the north, the north shore of the gabion revetment, forcing the water maneuver, take the bend top flush, resulting in shore erosion, resulting in 2 ~ # Pier 14 ~ 200 meters and embankment dam slope protection 20 meters; washed down the dam along the dam more than 50 meters, and in the dam to form a second small backflow, Wei Association roadbed security. In order to ensure the safe transport of the railway, we put 553m ~ 3 at the pier with 2 ~ # mounds, and hit the second row of rail piles along the bank of the river. Through this case of water damage, it shows that the existing protection and adjustment equipment can not meet the actual requirements. Second, pier protection 1. Silicate reinforcement and energy dissipation pile 1968 Scientific Research Institute of the Ministry of Railways and Zhengzhou Railway Bureau of the Yellow River Bridge in a group of silicification test, due to the river bed for the fine sand, combined with the capacity of construction machinery do not meet , Failed to actually use. Later, according to an example of the water destroyed in 1963, the ASTRI conducted field investigations and simulation experiments. If the influence of the circulation is excluded, it is possible to reduce the river bottoming brush. The main method to eliminate the circulation is the straight water flow. The best way to smooth the water flow is to build a passive pile at the upstream. Through experiments, the energy dissipation pile not only has the effect of straight water flow, but also can promote sediment back silting in the post to fill the pier scouring pit. According to the suggestion of the ASTRI, we use the energy-dissipating submersible pile for the first time on the Yellow River Pier protection. At the same time, we think: due to the main channel of the Yellow River flowing, the river has grass beaches, cross-ditch and other influences in the central part of the river can cause concentrated erosion. Therefore, when considering the scouring of the changing riverbed, we should conduct a comprehensive analysis and study and should not confine the two sides of the strait. 2. throwing stone cage and pre-cast stone cage