PCCP受载响应全过程有限元分析

Finite element analysis on whole process of load-bearing response of PCCP

基于陕西杨凌供水工程,建立预应力钢筒混凝土管(PCCP)的三维非线性有限元模型,研究了PCCP在全寿命各个阶段的受力特性和结构性能,得到PCCP各阶段应力状态和裂缝开展的规律。分析结果表明:(1)缠丝后由于管芯在预应力作用下的收缩变形,钢丝可能发生4%的预应力损失;(2)在预应力作用下管芯混凝土全截面受压,最大压应力在管道内侧,且由内到外线性递减;(3)在土荷载和管道自重作用下,砂浆层出现裂纹,管道发生椭圆形变形,在内水压力作用下,管道有外扩的趋势。

Based on Yangling Water Supply Project,a 3D nonlinear finite element model of prestressed concrete cylinder pipe(PCCP) is established herein,and then the bearing behavior and structure performance of PCCP at all the phases of its whole life are studied,thus the stress status and the cracking law at all the phases of PCCP are obtained.The analysis shows that:(1) after wiring of the prestressed steel wire,4% prestressing loss of the prestressed steel wire possibly occurs due to the contraction deformation of the pipe core under the prestressing effect;(2) under the prestressing effect,the full section of the pipe core concrete is pressurized along with the maximum compressive stress inside of the pipeline that presents a linear decreasing from the inside to the outside;(3) under the effects of both the soil-load and the self-weight of the pipe,fissures appear on the mortar coating with the oval deformation of the pipe,while the trend of the outward expansion of the pipe occurs under the effect of the internal water pressure.