1.3 Significance and Application Prospect of Under...
Nowadays slurry shield technology has been widely used in underwater tunnel construction in China for its safety，high efficiency，energy saving and environmental protection.With the gradual implementation of the national maritime strategy，regional economic integration and national large-scale channel construction plan，China's underwater tunnels have gradually developed to long distance，large diameter，large buried depth and high water pressure.The construction of underwater shield tunnels has good prospects and great potential.Table 1.2 is some representative large-diameter underwater tunnels under construction and planning in China.
Table 1.2 Some representative large-diameter underwater tunnels built or under construction in China
At present，the representative large-diameter underwater tunnels under construction mainly include Hong Kong Tunmen Chilajiao Tunnel（17.2 m in diameter，4.2 km in length），Wuhan Sanyang Road Tunnel（15.2 m in diameter，2.59 km in length），Nanjing Wuqiao Jiajiang Tunnel（15.0 m in diameter，1.59 km in length），Shantou Su'e Tunnel（14.5 m in diameter，6.4 km in length），Nanjing Heyan Road Crossing the Yangtze River Tunnel（14.5 m in diameter，2.98 km in length），etc.In the next 10-30 years，China plans to build five world-class subsea tunnels and nearly 100 underwater tunnels.These subsea tunnels include the Bohai Sea subsea tunnel from Dalian，Liaoning Province to Yantai，Shandong Province，the Hangzhou Bay subsea tunnel from Shanghai to Ningbo，Zhejiang Province，the Lingdingyang subsea tunnel connecting Hong Kong and Macao with Guangzhou，Shenzhen and Zhuhai，the subsea tunnel connecting Guangdong and Hainan Provinces across the Qiongzhou Strait，and Fujian and Taiwan.A subsea tunnel across the Taiwan Strait.It is foreseeable that our country will be in the near future and for a long time to come.
Hong Kong Tuen Mun Chiwajiao tunnel project is under construction，which adopts slurry pressurized shield construction with a diameter of 17.6 m.It is the largest diameter shield tunnel in the world at present.Bohai Strait tunnel and Qiongzhou Strait tunnel under planning will also adopt or plan to adopt slurry pressurized shield construction method.This shows that China's shield technology will develop in the direction of high water pressure，long distance and complex strata in the future，and will also face severe challenges in complex working conditions such as high water pressure，long distance，strong permeability，upper soft and lower hard，upper soil and lower rock composite strata.Therefore，it is necessary to systematically study and analyze the key technologies in the construction of large-diameter underwater shield tunnels in China，which is of great significance to promote the construction of underwater shield tunnels in China.