勐岗河大型悬索跨越管道成桥状态下非线性静力有限元分析

Finite element analysis on the nonlinear static force of Menggang River large suspension cable crossing pipeline under the finished state of bridge

云南楚雄—四川攀枝花天然气管道工程勐岗河悬索跨越管道因采用了一跨过河的方式架设,其在清管时产生的变形和应力不可忽视,为了获取清管动力响应特性的初始条件,需要先进行成桥状态下的非线性静力有限元分析。为此,首先基于ANSYS Workbench软件建立了1∶1的仿真模型;然后分析了存在一定起拱高度时,跨越结构在自身重力作用下各部分的应力大小;最后通过对跨越管道施加不同的静载荷,计算了管道的应力和位移并进行了校核。研究结果表明:①所建存在一定起拱高度的跨越结构仿真模型在自身重力作用下的应力与位移均低于许用值,并且与现场测试数据偏差较小;②试压工况下,管道最大应力位置出现在南岸桥面管道开始起拱处而非跨中部;③随着施加载荷的增加,管道的最大应力和位移也不断增大,但整体位移变化较小而应力最先达到许用应力值;④受起拱高度的影响,跨越管道在外载荷作用下各部分的位移变化和极限应力出现的位置均存在着特殊性。结论认为,该研究成果为后续同类型的跨越结构清管动力响应研究奠定了基础。

The Menggang River suspension cable crossing pipeline of the natural gas pipeline engineering from Chuxiong of Yunnan to Panzhihua of Sichuan is erected directly across the river,so the deformation and stress induced in the process of pigging shall not be ignored.In order to clarify the initial conditions of pigging dynamic response characteristics,it is necessary to perform finite element analysis on the nonlinear static force under the finished state of bridge.In this paper,a 1∶1 simulation model was firstly established based on the ANSYS Workbench software.Then,the stresses in different sections of the crossing structure under its own gravity load at a certain arch height were analyzed.Finally,by applying different static loads on the crossing line pipe,the stress and displacement of the line pipe were calculated and checked.And the following research results were obtained.First,the stress and displacement of the established simulation model of crossing structure with a certain arch height under its own gravity are lower than the allowable value,and the deviation from the field test data is smaller.Second,the maximum stress position of the line pipe under the working condition of pressure test appears at the beginning of the arch at the south bank bridge deck rather than at the center of the pipe.Third,with the increase of the applied load,the maximum stress and the displacement of the line pipe increase,but the overall displacement changes less and the stress first reaches the allowable stress value.Fourth,due to the influence of arch height,the displacement change of each part and the position of the ultimate stress of the crossing line pipe under external load have particularity.In conclusion,the research results lay a foundation for the subsequent researches on the pigging dynamic response of the same type of crossing structures.