双排钢板桩围堰在超深厚软土地基中的应用

以瓯飞一期围垦工程北闸双排钢板桩围堰为背景,介绍滨海超深厚软土地基中双排钢板桩围堰方案与施工技术。为研究双排钢板桩围堰结构安全性,对围堰抗倾覆和整体稳定进行演算,并利用有限元法对围堰施工全过程进行数值分析,得到不同施工工况下钢板桩、拉杆的受力状态以及围堰变形情况。研究结果表明:围堰结构安全性满足相关规范规程要求,有限元法计算围堰变形比实际情况大,说明该计算方法分析围堰结构安全是偏安全的;围堰前后排钢板桩及拉杆内力最大值工况出现不一致,建议围堰设计时应对施工全过程进行模拟,选择出各个结构最不利工况;围堰外侧海水位采用平均高潮位分析围堰结构安全存在一定的风险,建议采用设计高潮位。

Application of double-row steel sheet pile cofferdam in deep soft soil foundation

Taking the double-row steel sheet pile cofferdam in first phase reclamation project of Oufei as the project background,we introduce the construction scheme and technology for the double-row steel pile cofferdam built in coastal deep soft soil foundation.For studying the safety of double-row steel sheet pile cofferdam structure,we calculate the anti-overturning and the global stability of the cofferdam,carry out a numerical analysis of the whole construction process of cofferdam by the finite element method,and obtain the stress state of the steel sheet pile and tie rod and the deformation of the cofferdam under different construction conditions.The research shows that:the safety of cofferdam structure meets the specification requirements,the deformation of cofferdam calculation by finite element method is larger than that under the actual condition,which proves that the analysis of cofferdam structure safety by this method tends to be safety;the construction condition of the maximum internal force in the steel sheet pile and the tie rod is different between the front and rear of cofferdam.It is suggested that the whole construction process should be simulated during the cofferdam design to select the worst conditions of each structure.There are certain risks using the mean high tide level to analyze the safety of cofferdam structure,and the design high tide level is recommended.