离岸深水全直桩码头水平承载力简化计算

全直桩码头是一种适用于离岸深水海域的新型高桩码头结构型式,其破坏模式与传统高桩码头结构存在较大差异。通过有限元法研究了水平荷载作用下离岸深水全直桩码头结构破坏模式、桩侧土压力及桩身弯矩分布,并验算了规范中m法、P-Y曲线法和NL法的适用性。研究结果表明,水平荷载作用下,基桩的塑性破坏是结构失稳的控制因素,且结构失稳时桩身最大弯矩达极限弯矩值,在此基础上,结合简化计算方法计算了结构水平极限承载力。通过对比可知,基于m法的简化方法在小位移时与有限元法吻合较好,基于P-Y曲线法和NL法的简化方法在各种位移条件下与有限元法均吻合较好,且通过桩身极限弯矩与设计荷载作用下桩身最大弯矩之比计算结构安全系数的简化方法是合理的。

Simplified calculation methods for horizontal bearing capacity of all-vertical-piled wharf in offshore deep-water

All-vertical-piled wharf is a new type of high-pile wharf suitable for offshore deep seas， but its failure mode is quite different from the traditional type. The failure mode， earth pressure on piles and the bending moment along piles have been studied under wave loads and impact loads by use of FEM， and the applicability of m method， P-Y method and NL method for the all-vertical-piled wharf is verified. The analysis results show that in the horizontal limit state， plastic failure of the pile body is the key to the buckling damage， and the maximum bending moment along the piles reaches the ultimate bending moment. On this basis， the horizontal limit bearing capacity of structure has been calculated using simplified calculation methods. By comparison， m method is in good agreement with that given from FEM under small displacement conditions， P-Y method and NL method are in good agreement with that given from FEM in both large and small displacement conditions， and the simplified calculation method of safety coefficient through the ratio of the ultimate bending moment to the maximum bending moment along piles under design load is reasonable.