不同受力状态下沉入式大圆筒结构入土深度计算方法

On calculation methods of embedded depth large diameter cylinder under different loading states

沉入式大圆筒结构是一种适用于软土地基的码头、海岸及近海工程水工建筑物,沉入式大圆筒结构入土深度确定是该种结构稳定性设计的关键内容。假设圆筒绕筒轴线上某一点和绕筒母线上某一点转动二种变位模式;根据作用于圆筒上竖向力的大小,土对筒壁的摩阻力考虑竖直向上和向下二种情况;在土对筒壁的摩阻力竖直向上的情况下,考虑背离转动方向一侧地基土对筒底的反力作用。根据水平力、竖向力和力矩平衡条件,建立了沉入式大圆筒结构入土深度计算方法,对现有方法做了修改和完善。结合工程实例,对不同计算模式进行了比较分析,并研究了作用于圆筒上的竖向力和水平力对入土深度的影响。

Embedded large cylinder is a type of hydraulic structures in port, coastal and offshore engineering, which is especially suitable for soft soil ground. The calculation of its embedded depth is quite significant for its stability design. In this paper, there are two probable displacement models presented on the assumption that a cylinder may turn around a point either in the axes or in the generatrix . The direction of the friction force between soil and the cylinder varies according to the value of vertical forces. Furthermore, the force on the bottom of the cylinder, given by the ground on the side deviating from turning, has been taken into consideration while the friction force between soil and the cylinder is upward. With the consideration of horizontal forces, vertical forces as well as bending equilibrium equations, the computation of embedded depth of large diameter cylinder is put forward as modification of the existent. The different calculation models are compared and the effects of horizontal forces and vertical forces on embedded depth are investigated through a practical example.