桥墩沉井吸泥下沉冲刷试验研究

本项试验是确定黄河长东二桥施工期间沉井吸泥下沉时,是否危及附近既有桥安全,以及设计洪水流量条件下新桥的局部冲刷深度。为探索模拟沉井通过吸泥逐步下沉及其周围局部冲刷相似的试验方法,除一般局部冲刷常用的相似准则以外,还计入了沉井重力相似、吸泥(输沙量)相似、沉井外壁摩阻相似等方面的相似准则。并研究拟定了一些论证沉井逐步下沉时对附近既有桥安全影响的试验方案和判别方法。

Experimental study on the scour of air suck out sediment caused by bridge pier and open caisson subside

The experiment is used to determine whether to endanger the security of the nearby and existed bridges with the subsidence of the open caisson during the construction of the second Changdong bridge crossing the Yellow River and the local scour depth of the new bridge in the condition of design flood discharge.To investigate the similar method of the subsidence of the open caisson caused by air suck out sediment and local scour around,the model test should meet not only the common similarity criterions of local scour,but also some other similar criterions such as gravity similarity,suck out sediment similarity(sediment discharge) and friction similarity outside of the open caisson.Also some test schemes and discrimination methods that are used to demonstrate the security of the nearby and existed bridges due to the gradual subsidence of the open caisson are studied.