Study on Major Construction Disasters and Controlling Technology at the Qingdao Kiaochow Bay Subsea Tunnel

Abstract

Li, S.; Tian, H.; Xue, Y.; Su, M.; Qiu, D.; Li, L., and Li, Z., 2015. Study on major construction disasters and controlling technology at the Qingdao Kiaochow Bay Subsea Tunnel.The Qingdao Kiaochow Bay Subsea Tunnel was difficult because of complex geological conditions, including the 18 faults crossing the tunnel, large construction section, and high risks for collapse and water inrush. These conditions were considered as a background of this study. Geological disasters, such as collapse and water inrush, were introduced as the two main geological disasters during construction. Moreover, the advanced support pretreatment measures that aimed to address faults during construction and effectively prevented collapse disasters were introduced. For the water inrush disaster, geological forecasting was used to predict underground water location, and advanced grouting was adopted. The presented disaster control technologies were proven effective in the construction of the Qingdao Kiaochow Bay Subsea Tunnel. This study provides a certain reference value for disaster control technologies for subsea tunnel construction. ADDITIONAL INDEX WORDS:Subsea tunnel, construction disasters, collapse, water inrush, prediction, advanced grouting. ________________________________________________________________________________ INTRODUCTIONThe Qingdao Kiaochow Bay Subsea Tunnel connects the city to the auxiliary city of Qingdao, from the south Xuejiadao the north Mission Island, and beneath the Kiaochow Bay. The tunnel is 7,120 m long; the main tunnel length is about 6,170 m and the tunnel across the sea is approximately 3,950 m. The length of the tunnel is designed according to expressway ratings at a design speed of 80 km/h. The structure comprises two main tunnels and a service tunnel (Figure 1). The main tunnel axis a space of 55 m. The cross section of the tunnel is oval. The tunnel excavation cross section has a height of 11.2 m to 12.0 m and a width of about 15.23 m 16.03 m ( Figure 2); the tunnel has V longitudinal section, a maximum vertical gradient of 3.9%. The lowest point of the right line side elevation is −74.14 m, whereas that of the left is −73.69 m. The main tunnel of the sea section has a length of approximately 20 m to 30 m (Figure 3). The mining method is used for tunnel construction. At the YK6 +961-YK6 +915 section of the right line tunnel, a F4-4 fracture zone has developed, where the rock is seriously affected by the structure, and the full extent of the rock and the thickness of weathering are very different. Rock impermeability easily deteriorates under the influence of relaxation deformation, such that deformation and damage penetration may occur. Thus, the tunnel crosses areas with deformations, such as a broken belt, large cracks and joints, and a significant amount of water

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Discussion on the Waterproof and Drainage System of the Coastal Tunnel and Analysis of Water Pressure Law outside Lining: A Case Study of the Gongbei Tunnel

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