海底隧道工程盾构始发井水下封底混凝土施工

Construction Technology of Underwater Concrete Casting for Bottom-sealing of Launch Shaft of a Sub-sea Shield-driven Tunnel

深圳前湾过海隧道工程盾构始发竖井,直径18m,深28.54m,采用沉井法施工,水下混凝土封底,封底厚度4.5 m。属大体积混凝土施工,如何保质、保量、按期完成封底工作,是一个值得研究的问题。结合工程实际及相关计算理论,介绍了高水压海滩地层中盾构始发井井底水下大体积、大面积、封底混凝土施工技术。

The diameter and depth of the launch shaft of Qianwan sub-sea shield-driven tunnel in Shenzhen are 18 m and 28.54 m respectively. The lauch shaft is sunk by means of open caisson method. During the sinking of the launch shaft, underwater bottom-sealing is conducted. With a thickness of 4. 5 m, the concrete casting of the bottom-sealing construetion belongs to huge-volume concrete casting construction. It is worthy to make study on the concrete casting construction so as to fulfill the bottom-sealing with high quality and as per the schedule. On basis of the actual conditions of the project and the relevant theoreatical calculations, the article presents the construction technology of the huge-volume and large-cross-section underwater concrete casting for the bottom-sealing of the launch shaft situated in coastal ground.