预应力钢丝松弛对超大口径PCCP承载能力的影响

以南水北调中线工程为背景,利用光纤光栅计测取预应力钢丝实际松弛量。基于试验结果,采用非线性有限元法建立了PCCP承载数值计算分析模型,进行了钢丝预应力松弛对PCCP承载能力的影响研究。计算结果表明:在正常使用极限状态和弹性极限状态下,PCCP内压值随预应力松弛量的增加而减小;在承载能力极限状态时PCCP内压值保持不变。基于现场测试结果和计算结果,评价了预应力松弛对PCCP承载能力的影响,为PCCP的生产和运行积累了工程经验,为制定超大口径PCCP标准以及质量验收提供依据。

Influences of relaxation of prestressed steel wires on bearing capacity of prestressed concrete cylinder pipes with large calibers

With regard to the Middle Route Project of South-to-North Water Diversion,the relaxation of prestressed steel wires was measured by use of fiber bragg grating gauges.A mathematical model for the bearing capacity of prestressed concrete cylinder pipes(PCCPs) was established on the basis of the test results by means of nonlinear finite element methods.The influences of relaxation of prestressed steel wires on the bearing capacity of PCCPs were analyzed.The calculated results show that the bearing capacity of PCCPs decreases with the increase of relaxation of steel wires under the working and elastic limit states,and it keeps unchanged under the limit state of strength.The influences of relaxation of prestressed steel wires on the bearing capacity of PCCPs were evaluated based on the test and calculated results so as to gather experience for manufacture and construction of PCCPs with large calibers and to provide a basis for preparation of the relevant criteria.