弯曲过渡破坏条件下锥体结构的冰荷载分析  

Ice load acting on conical structures during the transition of ice bending failure mode

作　　者：李锋[1] 韩雷[1] 岳前进[1] 

机构地区：[1]大连理工大学工程力学系,辽宁大连116024

出　　处：《水利学报》2006年第9期1078-1084,共7页Journal of Hydraulic Engineering

基　　金：国家863计划资助项目(2001AA602015)

摘　　要：现场观测显示,作用在锥形抗冰结构上的冰破坏力变化与冰弯曲破坏的模式过渡相联系,最大冰力在过渡条件下出现。为了确定这一冰破坏力,本文采用半圆环域的薄板模型求得弹性力学解,在小挠度条件下得到了分别与两种弯曲破坏模式相对应的冰力表达式,它们都是冰断裂长度平方的函数。由此确定了过渡破坏条件下的冰荷载。得到过渡的临界条件为锥面的水线半径与冰的环向裂纹的半径之比等于0.467。过渡冰力(无量纲化)的竖向分量为一常数6.28。分析得到的冰力的竖向和水平两个分量通过两组模型试验进行比较得到了验证。研究表明,如果冰的破坏模式落入过渡区,通常在静冰力分析中采用的以楔梁型破坏为基础的冰力模型可能低估冰力的幅值。Field observation shows that the variation of ice breaking force acting on conical ice-resistance structures is related to the transition of failure mode of ice bending. The maximum peak force occurred during transition. By using the elastic thin plate model with semi-cirque domain and deducing its solution by means of theory of elasticity, two kinds of ice load with different bending modes are obtained under small deflection condition. The loads are functions of the square of the breaking length of ice. The ice load under critical condition of mode transition is therefore obtained. The critical condition of mode transition is the ratio of water line radii of the cone to radii of the circumferential cracking of ice equal to 0.467. The vertical component of the dimensionless ice force during transition is approximately equal to a constant. The validity of the analyses of the vertical and horizontal components of ice force is verified by experimental result. It is found that the amplitude of dynamic ice force may be underestimated if the ice force is determined based on the wedged beam failure model.

关 键 词：冰荷载 锥体结构 破坏模式 过渡 

分 类 号：TU312.1[建筑科学—结构工程]