运营期船桥碰撞时大型哑铃型承台群桩基础承载变形特性

对某特大桥运营期承受船撞荷载时的索塔哑铃型承台群桩基础与土体相互作用进行了三维弹塑性静态有限元分析。桩土界面间设置三向的弹簧,横桥向与纵桥向和竖直方向的弹簧分别模拟水平荷载和竖向荷载下桩土相互作用,以便能较好模拟竖向荷载与水平荷载共同作用下大型群桩基础受力变形特性。比较研究分析了索塔哑铃型承台群桩基础最大冲刷方案和护底方案在船撞击时桩身轴力分布、桩身水平剪力分布及桩身弯矩分布等特性,并与其离心模型试验成果进行了比较。结果表明:护底方案在桩身弯矩等方面远比最大冲刷方案的小而表现出能较好抵御船撞荷载。

Characteristic of dumbbell shaped pile-cap and group piles during collision of ship and bridge

Interaction between dumbbell shaped pile-cap and group piles in a super large bridge was analyzed with ANSYS software of 3D elastic-plastic finite element during the collision of ship and bridge. Horizontal and vertical spring in the interface between piles and soils was used to model the pile-soil-pile interaction under the vertical and horizontal load. Two design schemes of maximal scour and resistant scour were compared with the characteristics of axial force, sheafing force, and moment of piles, etc. The computed results of the two design schemes were compared with those of centrifuge modelling. It could be seen that resistant scour scheme was better than the maximul scour scheme in the resistance of impact load of ship and bridge from the point of moment of piles etc.