长江下游大型沉井基础局部冲刷计算公式研究

大型沉井基础在长江下游大跨径跨江大桥工程中应用越来越多,基础局部冲刷深度预测是设计时需要重点考虑的问题之一。国内外对桥梁基础局部冲刷做了大量的研究并建立了局部冲刷计算公式,由于长江下游大型沉井基础规模越来越大,原有局部冲刷深度的预测公式存在一定的局限性。在常泰大桥超大沉井基础局部冲刷试验成果的基础上,结合长江下游南京以下跨江大桥沉井基础局部冲刷试验成果,通过量纲分析及多元回归法建立了大型沉井基础局部冲刷计算公式,并应用试验资料及实测资料进行了较好的验证。该公式计算结构简单,可供长江下游大型沉井基础局部冲刷深度估算参考和应用。

Study on local scour calculation formula of large open caisson foundation in the lower reaches of the Yangtze River

Large open caisson foundation is more and more used in the project of long-span river crossing bridge in the lower reaches of the Yangtze River. The prediction of local scouring depth of foundation is one of the key problems to be considered in the design. A lot of researches have been done on the local scour of bridge foundation at home and abroad, and the calculation formula of local scour has been established. Due to the increasing scale of large open caisson foundation in the lower reaches of the Yangtze River, the original prediction formula of local scour depth has some limitations. Based on the local scouring test results of the super large open caisson foundation of the Changtai Bridge and the local scouring test results of the open caisson foundation of the bridge over the Yangtze River below Nanjing, we have established a calculation formula for the local scouring of the large open caisson foundation using dimensional analysis and multiple regression method, which is well verified by the test data and measured data. The formula has a simple calculation structure and can be used as a reference as well as an application method for the estimation of local scouring depth of large open caisson foundation in the lower reaches of the Yangtze River.