软弱地基下大型沉管隧道管段预制关键技术

Key Technology of Prefabrication of Tube Segment Used for Large-Scale Immersed Tube Tunnel with Soft Foundation

基于天津市海河隧道位于高震区软弱地基下,进行沉管隧道管段预制设计与施工。通过对坞底软基处理、大型模板设计、混凝土防裂、耐久性能、管段干弦值控制等方面进行研究,采取试验先行,后指导施工的研究方法,总结出合理的施工工艺及技术措施,保证了85 m×36.6 m×9.65 m,重约3万t大型沉管隧道管段制作质量。

Haihe River Tunnel in Tianjin belongs to immerged tube tunnel at high seismic intensity region,so the tube segments need to be prefabricated under effective design and reasonable construction process.Through researching into soft foundation treatment,large-scale formwork design,concrete anti-cracking,structure durability,geometric size controlling and other aspects were researched,adopting the research method of 'experiment first,then guiding construction',the reasonable construction process and technical measures were summarized,which can ensure the prefabrication quality of the tube segment(its dimensions are 85 m×36.6 m×9.65 m,about 30 000 tons in weight) of large-scale immerged tube tunnel.