后张预应力圆形隧洞衬砌纵向应力计算

隧洞后张预应力衬砌施工过程中,因张拉锚索挤压衬砌环产生环向预压应力,同时,还会在衬砌环中产生纵向拉应力,若处理不当,其值较大,可以使衬砌发生环向裂缝,应予重视.提出等效弹性地基梁算法,用以计算薄壁圆筒的纵向内力、应力和变形,适于手算和电算,可供工程应用;通过对不同张拉方案计算结果的分析,提出减小纵向应力,保障安全应用的建议.

Longitudinal stress computation of post-tensioned prestressing concrete circular tunnel

In the process of lining construction of post-tensioned prestressing concrete circular tunnel, for the pressing of tensioned anchorage cable, it will produce the circumferential pre-compression stress and longitudinal tensile stress in lining ring. If treated improperly, the stresses are comparably large and the circumferential cracks will emerge in lining concrete. It should be paid enough attention. The equivalent elastic foundation beam method for longitudinal internal force, stress and deformation computation of thin cylinder is suggested. It is suitable for manual and computer computation and can be used in engineering. Through the analysis on computation results of different tensioning schemes, the suggestions of reducing longitudinal stress for application safety are put forward.