On the morning of January 10，The world's longest high-speed rail submarine tunnel shield machine jointly built by China Railway Construction Heavy Industry and China Railway 11th Bureau“Dinghai”Offline in Changsha Primary Industry Park of Railway Construction Heavy Industry。

In ancient times, there was a sea dragon.，Today there is a Tielong through the sea.，“Dinghai”The cutter head is painted“Dragon King of the East China Sea”Pattern，Have“Shenlong Zhenhai，Good luck”A beautiful moral。The equipment is about 130 meters long.，Maximum excavation diameter up to 14.57 meters，Will be applied to the world's longest、The largest diameter high-speed rail undersea tunnel——Construction of Jintang Submarine Tunnel on Yongzhou-Zhoushan Railway。

Jintang Submarine Tunnel of Yongzhou-Zhoushan Railway“Four high、The Big Three、Two Complications”Difficult problems in engineering construction，With large excavation diameter、The rock strength is high、The lithology is quite different、High construction water pressure、Docking is difficult、High precision requirements and complex geological conditions.。

 “Dinghai”The slurry balance shield machine combines the engineering characteristics of the project.、Key and difficult points and rich construction and technical experience of China Railway Construction Corporation in the past，Adopt a series of targeted design and a number of advanced technologies，It can effectively deal with various complex geological and working conditions.，It will provide strong support for the smooth construction of Jintang Submarine Tunnel.。

Jintang Submarine Tunnel Project of Yongzhou Railway is one of the ten landmark projects in the construction of major corridors in Zhejiang Province.，After the completion of the project，It will fill the blank of the last district and city in Zhejiang Province without access to railways.，Further strengthen the integration effect of Ningbo and Zhoushan，Accelerate the full integration of Zhoushan and Ningbo into the high-quality integrated development of the Yangtze River Delta and“The Belt and Road”Construction。