基于离散元方法的竖直群桩冰荷载分析

Analysis of ice load on vertical pile group based on discrete element method

在高纬度海域或高寒地区的江河中,碎冰对海洋平台桩腿和桥墩等直立群桩结构产生很大的冲击作用,并在一定条件下造成不同程度的破坏。依据碎冰在自然条件下的离散分布特性,采用Voronoi切割算法构造随机分布和具有非规则几何形态的碎冰初始状态,在此基础上采用若干个具有黏结-破碎功能的球形颗粒构造具有一定厚度、尺寸和形状等物理参数的河冰离散单元模型,将竖直群桩简化为刚体结构,从而对碎冰的运移及其对群桩的冲击作用进行数值模拟。在此基础上可确定碎冰撞击下的群桩冰荷载,并分析冰块尺寸、冰速和冰厚对桩结构所受冰荷载的影响。

In the seas and rivers in high-latitude regions,the broken ice floes can generate obvious ice load on offshore platform piles and bridge piers,and even cause damage of the vertical piles.Based on the discrete distribution characteristics of ice floes under natural conditions,the Voronoi cutting algorithm was used to construct the initial state of randomly-distributed broken ice floes with irregular geometric shapes.The discrete element method was adopted to simulate the drifting process of ice floes and the interaction between ice floes and vertical piles.The ice floe model with certain thickness,size,shape and other physical parameters was constructed with bonded spheres with consideration to their failure effect.The vertical piles were simplified as rigid structures.A numerical simulation was conducted to determine the ice load on the pile group under the impact of ice floes,and analyze the effects of ice size,ice velocity and ice thickness on the ice load of pile structures.