采用X形桩的遮帘式板桩码头结构静力分析

Static analysis of covered sheet pile wharf structure using X-shaped piles

X形桩是一种反拱曲面异型桩,相比于同等截面积的矩形桩和圆形桩,X形桩具有更大的截面周长和惯性矩,受力性能更好。结合京唐港32#泊位遮帘式板桩码头结构,以X形桩代替传统的矩形桩,研究其对结构静力的影响。结果表明:相同桩间中心距时,以X形桩替代后可减小前墙弯矩;在同等桩间净距1.75 m下,两类模型的前墙最大弯矩基本相同。相同荷载作用下,前墙位移主要受桩间中心距影响,X形桩形状影响效应很小;锚碇墙水平位移受桩间中心距和遮帘桩形状的影响均很小。桩间中心距、净距与桩间土体土拱效应直接相关,对前墙弯矩、土压力、遮帘桩弯矩等有显著影响。桩间中心距为4.05 m或桩间净距为1.75 m时,结构内力改善效果较优,可采用该间距的X形桩替代矩形桩,节约工程造价。

X-shaped pile is a type of heterotypic pile with inverted arch curved surfaces. Compared with rectangular and circular piles with the same area of cross-section,X-shaped pile has a longer perimeter and larger inertia moment of the section,resulting in better mechanical properties. Based on the covered sheet pile wharf structure of 32#berth in Jingtang Port,we apply X-shaped piles to replace original rectangular covered piles and study the influence of X-shaped pile on the static behavior of wharf structures. The results show that at the same central distance between piles, the moment of the front wall reduces when replacing rectangular piles with X-sectional piles,and the maximum moment of front walls is similar for two types of models at the same net distance of 1. 75 m between piles. Under the same load,the displacement of the front wall is greatly correlated with the central distance between piles but hardly affected by the shape effect of the X-type pile. In contrast,the displacement of the anchor wall is hardly influenced by these two factors. The soil arching effect is directly correlated with the central and net distance between piles. This effect greatly affects the moment of the front wall,the soil press on the front wall,and the moment of covered piles. At a central distance of 4. 05 m or a net distance of 1. 75 m between piles,a great improvement of internal force is obtained. X-shaped piles at this spacing can be used to replace normal rectangular piles for saving construction costs.