Abstract:

The Shantou Bay crosssea tunnel is a control project of the Shantou section of national highway G228 with a complex overall design. The authors consider how to construct the Shantou Bay crosssea tunnel scientifically, safely, and economically based on the control factors for urban planning, the environment for engineering construction, and sensitive environmental concerns on both sides of the strait. Thus, the key problems related to site selection, connection, buried depth, section layout, ventilation, disaster prevention and evacuation for the crosssea tunnel are studied and visualized using engineering analogy, numerical calculations, and model analysis. Some of the findings are as follows: (1) The location and connection of the crosssea tunnel should be determined based on urban planning, traffic characteristics, road network structure, and land use along the line; these are key to controlling risk, reducing investment, and ensuring traffic flow. (2) Based on the scouring envelope of the seabed evolution model, the minimum soil cover for the shield section should meet the safety requirement for antifloating during excavation and operation, and the shield section should prevent longdistance crossing of the upper soft and lower hard strata. (3) In the crosssea section, a ventilation scheme for the segmented longitudinal and key smoke exhaust is used. (4) Longitudinal and horizontal evacuation modes with a pedestrian slide or stairs are used in the shield and opencut sections, respectively; these modes guarantee disaster prevention and evacuation of the crosssea tunnel in an area with high seismic intensity.

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Key words:

crosssea tunnel, largediameter shield tunnel, overall design, theoretical research, disaster prevention and evacuation