Hong Kong-Zhuhai-Macao Bridge
Distribution Laws of Fire Temperature Fields in Immersed Tunnel: A Case Study of Hong Kong-Zhuhai-Macao Bridge Immersed Tunnel Project
Tunnel Construction,Vol 38,No. 05
【Abstract】 The large testing platform for immersed tunnel is established to analyze the distribution laws of the temperature field and its influencing factors when a tunnel fire breaks out. Meanwhile, the combination method of physical testing (1:1 full-scale fire test) and numerical calculation FDS are applied. Some conclusions are drawn as follows: (1) Longitudinal wind speed within limits can decrease the maximum temperature of tunnel crown top effectively when fire breaks out in tunnel. (2) The maximum temperature of tunnel crown top and fire behavior are related to fire types obviously. (3) The high temperature resistance safe position of the tunnel equipment is below 3.5 m of tunnel sidewall in case of fire source heat quantity of 50 MW. (4) The fire maximum temperature is positively related to heat release rate (HRR) and longitudinal wind speed.
Scientific and Technological Innovation and Operation-related Issues for Island-Tunnel of Hong Kong-Zhuhai-Macao Fixed Link Project
Tunnel Construction,Vol 38,No. 10
【Abstract】 The author explains why a giant undersea immersed tube tunnel was selected for the sea area of the main channel of the east side of the Hong Kong-Zhuhai-Macao Fixed Link Project, instead of employing a bridge or shield tunnel; and summarizes several domestic and international leading innovative technologies applied in the island-tunnel construction of the Hong Kong-Zhuhai-Macao Fixed Link Project, including the use of huge self-stabilized steel cylinders as retaining structure of foundation pits for constructing the artificial islands, the large-area and ultra-deep “sand compaction pile (SCP) composite foundation” reinforcement technology, “semi-rigid segment joints”, “sandwich” steel-RC combined inverted-trapezoid closure joints, and crack control and anti-corrosion/durability design for RC tube structure. All these technologies reflect Chinese wisdom and Chinese speed. The author also points out some technical issues to which attention should be paid after the immersed tube tunnel of the project is put into operation: (1) Will the post-construction settlement and differential settlement of the immersed tube tunnel further develop after the project is open to traffic? How much is the final convergence value? If it exceeds the limit, what control measures should be taken? (2) How to deal with the issue that the joints of large/small elements or segments are open? How to ensure that all the large and small joints between segments of the tube are “watertight”? Furthermore, the author presents some suggestions and control measures: (1) For excessive post-construction settlement (especially differential settlement) spotted on large joints, it is suggested to incorporate “micro-disturbance grouting” for post treatment. (2) If a joint opens under the excessive positive bending moment at the floor slab, it is believed that the open joint on the floor slab can be closed again by cutting off some prestressed tendons in the roof slab of the segment to reduce the positive bending moment of the section.
Construction of a Long-distance and Shallow-buried Tunnel Using Curved Pipe Roof and Freezing Method: Gongbei Tunnel of Hong Kong-Zhuhai-Macao Bridge Project
Tunnel Construction,Vol 39,No. 01