深水高桩嵌岩桥墩抗撞能力分析

以2007年6月15日广东九江大桥船撞倒塌事故中被撞深水高桩嵌岩桥墩为研究对象,采用更新拉格朗日列式考虑结构几何非线性,Hognestad模型和Mander模型分别模拟无约束和受约束混凝土,理想弹塑性模型模拟钢筋作用;考虑桩基和周围介质的非线性作用,采用P-Y、T-Z和Q-Z弹簧模拟计算了单个高桩桥墩的抗撞能力,揭示了桩顶与承台结合处截面为深水高桩桥墩的薄弱环节。在此基础上,分析了桩基直径、河床冲刷与淤积程度、桩基倾斜角度、桩身配筋率、水下砂土内摩擦角对深水高桩桥墩抗撞能力的影响。

Quasi-static Analysis of Anti-collision Capacity of High Piers Embedded in Rock under Deep Water

The impacted pier in the vessel collision accident happening in Jiujiang Bridge on June 15,2007 was taken as the research object.In order to obtain an reasonable result of quasi-static force against vessel collision,the renewed Lagrange′s equitation was used to calculate the nonlinear geometry effect of the structure,the Hognestad and Mander model were used to simulate the non-constraint and constraint concrete respectively and the ideal elastoplastic model was used to simulate the steel bar.Besides,P—Y,T—Z and Q—Z springs were used to simulate the interaction effects between piles structures and soil.Then the top section of pile being weak part of pier structure under quasi-static force was pointed out.In the basis of these works,the influence of several factors on collisonresistant capacity of high pile pier in deep water was analyzed and the factors include the diameter of piles,the erosion and silting-up of riverbed,the inclined angle of piles,the ratio of reinforcement of piles and the internal friction angle of soil under water.