方沉箱浮游稳定特性

Floating stability characteristic of rectangular caisson

针对某港码头方沉箱,探讨了影响方沉箱浮游稳定特性各因素(定倾半径、质心到浮心的距离、定倾高度和沉箱吃水)随着沉箱密度和前舱加水高度的变化规律。结果表明:在前舱加水高度不变的情况下,方沉箱定倾半径和质心到浮心的距离随着沉箱密度增加而减小,定倾高度和沉箱吃水则相反;在沉箱密度不变的情况下,各因素随着沉箱密度的变化规律同前舱加水高度。前舱加水高度过高,会引起方沉箱的浮游由稳定平衡变为不稳定平衡,存在较大风险,而规范中并未有所体现,建议设计时加以考虑。同时在满足浮游稳定的前提下,尽量减少前舱加水高度从施工上来说是很有必要的。

This paper discusses the variation law of factors （metacentric radius, distance from the gravity center to the buoyant center, metacentric height and draft of caisson） impacting the floating stability of the rectangular caisson with the change of the unit weight of concrete and the height of ballast water in the front compartments of the caisson in some port. The results show that if the ballast water in front compartments of the caisson remains the same, the metacentric radius and the distance from the gravity center to the buoyant center will decrease with the increase of unit weight of concrete, but the metacentric height and the draft of caisson will increase. The initial stable equilibrium of the caisson will be changed into unstable equilibrium because of higher water level in the front compartments of the caisson. The risk is not included in the codes and should be considered in design. The decrease of the height of ballast water in the front compartments of the caisson under the premise of satisfying the floating stability is necessary for the construction.