自锁头-预应力锚索基础在海洋平台观测塔工程中的应用

Utilize of Self-locking-prestressed Steel Cable Foundation in Offshore Platforms

自锁头-预应力锚索基础由混凝土柱靴、自锁头、钢绞线组成。上部结构传来的压力、弯矩由混凝土柱靴承担,剪力则由压力引起的摩擦力承担。由于预紧力的存在,自锁头-预应力锚索基础始终处于受压状态,有效地避免了海水冲刷对基础的影响。本文结合工程实例,利用底部自锁头的自锁原理,将砂浆与岩石的抗剪转换成自锁头与岩石的抗压,解决了岩石脆性及不均匀性问题,提高了基础安全性能。由于钢绞线疲劳应力变化幅值远低于其疲劳允许应力幅值,说明基础抗疲劳性能好。与桩基础相比,自锁头-预应力锚索基础大幅降低钻孔难度,可降低造价并缩短工期,且自锁头-预应力锚索基础承载力高,适用于深海复杂环境海洋平台结构。

self-locking-prestressed steel cable foundation is composed of concrete pillar boots self-locking steel strand.The pressure and bending moment from the superstructure are assumed by the concrete pillar boots while the shear force is assumed by the friction caused by the pressure.The foundation is always under compression because of preload which can avoid the impact of sea water erosion on the foundation effectively.In this paper based on the self-locking principle the shear resistance of the rock was converted into the compression of the rock which solved the problems of brittleness and non-uniformity of rock and improved the safety performance of foundation.The fatigue stress variation amplitude of steel cable was lower than its fatigue stress amplitude so the foundation had good anti-fatigue performance.Compared with pile foundation self-lockingprestressed steel cable foundation could greatly reduce the difficulty of drilling reduced the cost and shorten the construction period.Moreover the foundation had high bearing capacity which was suitable for offshore platform structure in deep sea complex environment.