Using a large tunnel boring machine, the contractor starts excavating the southbound tube from the north portal of the tunnel. The contractor also excavates a cavern at the Lau Shui Heung site using the drill-and-blast excavation method, allowing the tunnel boring machine to turn around in the cavern after breaking through the tunnel boring machine section of the southbound tube and begin the northbound tube excavation. (A mimic photograph is shown.)
Using a large tunnel boring machine, the contractor starts excavating the southbound tube from the north portal of the tunnel. The contractor also excavates a cavern at the Lau Shui Heung site using the drill-and-blast excavation method, allowing the tunnel boring machine to turn around in the cavern after breaking through the tunnel boring machine section of the southbound tube and begin the northbound tube excavation. (A mimic photograph is shown.)
Using a large tunnel boring machine, the contractor starts excavating the southbound tube from the north portal of the tunnel. The contractor also excavates a cavern at the Lau Shui Heung site using the drill-and-blast excavation method, allowing the tunnel boring machine to turn around in the cavern after breaking through the tunnel boring machine section of the southbound tube and begin the northbound tube excavation. (A mimic photograph is shown.)
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