大型桥梁钢沉井下沉过程局部冲刷研究

钢沉井下沉过程中局部冲刷的研究是同类桥墩设计和施工十分关心的重要课题,它对保证钢沉井安全有效施工、桥梁设计中施工期桥墩最大冲深、失稳和安全计算有重要参考价值。通过室内试验研究了钢沉井下沉过程中的局部冲刷机理和冲刷形态,探讨了桥墩下部钢沉井基础施工的相对高程对局部冲刷的变化规律,并将试验研究所获得的局部冲刷规律和影响因素,采用墩型系数方法引入局部冲刷计算中,给出了计算公式。研究成果补充了国家行业规范内容,对同类工程的设计、施工具有借鉴和指导意义。

Research on local scour during settling of steel caissons for large-scaled bridges

Research on local scour during settling of steel caissons is an important topic for design and construction of large-scaled bridge piers.It is helpful to effective construction of steel caissons and calculation of inclination of different scour surfaces under the action of currents during construction,the maximum scour depth,instability as well as safety during the design of bridges.Through lab tests,local scour mechanism and scour patterns are studied during settling of steel caissons.Relationship between the relative elevation for construction of foundation of steel caissons at the lower part of bridge piers and local scour of riverbed is discussed.For convenience of application and in accordance with the existing national codes in China,the law of local scour and the influencing factors obtained during tests are both introduced in the calculation of local sour by use of pier shape coefficient.And corresponding equations are put forward.The present achievements have improved the contents of the existing national codes.They are useful to construction and design of similar projects.