洞嘎雅鲁藏布江大桥深基坑支护方案设计与施工技术

On the Design of and Construction Techniques for the Supporting Scheme of the Deep Pit Foundation of the Yarlu Zangbo River Bridge at Dongga

针对洞嘎雅鲁藏布江大桥深基坑,综合考量各种基坑支护方案,最终采用了钢筋混凝土防护桩加止水帷幕方案。由于基坑深度达到了15.3m,为了减小支撑结构的受力,在开挖基坑之前,进行了双浆液封底施工作业。采用理正深基坑7.0对支护结构进行了检算,并且用midas对腰梁和内撑结构进行了计算,计算结果表明防护桩和围囹的强度和刚度均满足要求。经过现场测量,防护桩的水平位移与计算结果相比,误差很小。这可为相似基坑的设计和施工提供参考。

With the deep pit foundation for the Yarlu Zangbo River Bridge in min d ,th e various supporting chemes for deep pit foundation are comprehensively considered,upon the basis of which the scheme of the reinforced concrete protective pile＋the water-stopping curtain is finally chosen. Owing to the fact that the foundation pit is as deep as 15. 3 m,in order to reduce the stress of the supporting structure,the double slurry sealing is carried out before the excavation of the pit. The supporting struc-ture is calculated with the Leezheng 7. 0 for deep pit foundation, and the waist beam and the inner support structure are calcu-lated with the Midas. The calculated results show that the protective pile, and the waling strength and stiffness are up to the requirements. And after the site measurement,it is found that the horizontal displacement of the pile is quite in agreement with the calculated results with little errors. The project may serve as a useful reference for the design and construction of other similar foundations.