海中筑岛柔性组合围堰结构受力与变形特性

Stress and deformation characteristics of flexible composite cofferdam structure for building islands in sea

为了解决海上地连墙建设中,海上施工平台结构施工周期长、造价高等难题,利用锁扣钢管桩与工字形板桩组合围堰进行海中筑岛,围堰外侧设置平行钢丝索进行柔性约束,形成海中“锁扣钢管桩+工字形板桩+平行钢丝索”的柔性组合围堰结构。以传统刚性围箍和无围箍组合围堰结构作为对照,根据现场监测数据,对柔性组合围堰结构受力与变形特性进行分析。结果表明:与常规刚性围箍结构相比,在同样吹填土压力荷载作用下,柔性围箍结构中桩身最大弯矩减小约50%;无围箍结构中桩顶最大水平位移过大;在不均匀堆载作用下,刚性围箍自身应力会发生突变,而柔性围箍始终受拉,应力均匀分布。监测结果表明,柔性组合围堰结构实测应力、变形与计算一致性良好。

The construction of offshore platform structure has long period and high cost in the construction of diaphragm wall in sea.To solve the problem,the combined cofferdam of locking steel pipe pile and I-shaped sheet pile is used to built islands in the sea,and the parallel steel wire cable is set outside the cofferdam for flexible restraint,forming a flexible composite cofferdam structure of“lock steel pipe pile+I-shaped sheet pile+parallel steel wire cable”in the sea.Compared with traditional rigid hoop and the non-hoop composite cofferdam structure,based on field monitoring data,stress and deformation characteristics of the proposed flexible hoop composite cofferdam structure are analyzed.The results show that compared with the conventional rigid hoop structure,the maximum bending moment of the pile in the flexible hoop structure is reduced by about 50%under the same dredger fill pressure load.The maximum horizontal displacement of the pile top is too large without the hoop structure.Under the action of uneven loading,the stress of the rigid hoop will change abruptly,while the flexible hoop is always tensioned and the stress is evenly distributed.The monitoring results show that the measured stress and deformation of the flexible composite cofferdam structure are in good agreement with the calculation.