后张预应力张拉阶段纵向应力与张拉方案研究

Study on longitudinal stress of post-tensioned prestress lining and tension schemes

为了解决在隧洞后张预应力衬砌施工中因张拉锚索挤压衬砌环,衬砌在形成环向预压应力的同时,会产生纵向拉应力,致使衬砌有可能发生环向裂缝的问题。以南水北调中线穿黄隧洞工程为例,对穿黄隧洞预应力衬砌张拉阶段的纵向应力与张拉方案进行了研究,提供了关于张拉阶段纵向应力与张拉方案的研究方法。结果表明:后张预应力衬砌施工时出现的环向裂缝问题,可以通过选择合理的张拉方法予以解决。可供具有圆筒形轮廓的预应力工程研究张拉方案时参考。

In the construction of post-tensioned prestress lining in a tunnel,because the tensioned anchor squeeze lining ring,the longitudinal stress and circumferential pre-stress will produce,resulting in the circumferential cracks of the lining.Taking the Middle Route Project of South-to-North Water Division as an example,we study the longitudinal stress and tension schemes and provide methods for studying longitudinal stress in tension phase and tension scheme.The results show that the problem of circumferential cracks can be solved by choosing reasonable tension scheme.The study results provide reference for tension scheme selection of circular-type pre-stressed project.