On March 26th, the world's first undersea high-speed rail tunnel designed for 350 km/h operation－the Shantou Bay undersea tunnel on the Shantou-Shanwei High-Speed Rail  was successfully completed. This mega project has set four world records, marking new technological heights in global undersea high-speed rail tunnel construction.

Breakthrough ceremony site (Photo by Fan Shaowen)

The Shantou-Shanwei High-Speed Rail is a crucial part of China's "Eight Vertical and Eight Horizontal" railway network. The 162-km line connects Shantou Station to Shanwei Station via Jieyang City, with a design speed of 350 km/h.

Workers from Guangdong Guangshan Railway Company celebrate the milestone

Workers from China Railway 14th Bureau Group celebrate the breakthrough (Photo by Chen Shi)

The 9,781-meter-long tunnel crosses Shantou Bay's main shipping channel, passing through 17 fault zones, including 8 active faults. Construction overcame multiple world-class challenges including magnitude-8 earthquakes, 100-meter water pressure, high chloride erosion, complex fault structures, and varying rock hardness. The tunnel boring machine(TBM) excavated through extremely hard granite with 200 MPa compressive strength - a rare challenge in global tunneling history.

Multiple construction teams collaborated with China State Railway Group Co., Ltd. and academic experts in China to solve technical challenges through rigorous research and on-site verification.

The completion of Shantou Bay undersea tunnel has set multiple records, the world's first 350km/h single-tube double-track high-speed rail undersea tunnel, the world's largest excavated diameter for a completed rail undersea tunnel, China's undersea rail tunnel crossing the most active faults, and China's undersea tunnel with the highest water pressure resistance.

Post-breakthrough construction will immediately advance to critical phases including long-distance shield machine pushing without excavation and in-tunnel disassembly by the TBM - both representing world-first applications for ultra-large diameter tunnel boring operations.

Upon full completion, the Shantou-Shanwei High-Speed Rail will achieve three transformative milestones, direct access to downtown Shantou, increased daily capacity from 24 to over 50 train pairs, and seamless connection with the Zhangzhou-Shantou High-Speed Rail currently under construction. This integration will establish a new high-capacity north-south passenger corridor linking China's three major coastal economic zones - the Pearl River Delta, West Taiwan Strait Economic Zone, and Yangtze River Delta regions.

Source:Lingnan on the Cloud

世界首座设计时速350公里单洞双线海底高铁隧道正式贯通

3月26日，世界首座设计时速350公里单洞双线高铁海底隧道——汕汕高铁汕头湾海底隧道正式宣告贯通。这项超级工程以四项纪录，刷新了全球高铁海底隧道建设的技术高度。

汕汕高铁是国家"八纵八横"高速铁路网沿海通道的重要组成部分，线路起自汕头站，途经汕头市、揭阳市、汕尾市，终至汕尾站，正线全长162公里，设计时速350公里。

据介绍，汕头湾海底隧道全长9781米，横跨汕头湾主航道海域，洞身穿越17处断层破碎带（含8处活动断层），建设过程中要克服8级高烈度地震、近百米超高水压、高氯盐侵蚀，多断层构造，地层软硬不均、极硬岩等多个世界级施工难题。同时，盾构机在高达200MPa抗压强度的极硬花岗岩地层掘进，施工难度国内外罕见。

隧道建设过程中，多个参建单位精心策划、周密部署，多次邀请国铁集团及国内院士科研团队开展重大科研立项攻关，现场论证把关，合力攻克建设难题。

据介绍，汕头湾海底隧道贯通，一举创造了多项纪录：世界首座设计时速350公里单洞双线高速铁路海底隧道、世界已贯通最大开挖直径铁路海底隧道、国内穿越活动断层最多的铁路海底隧道、国内开通水压最大的海底隧道。

隧道贯通后，还将紧张推进盾构机长距离空推、盾构机洞内拆解等任务，超大直径盾构空推及盾构机拆解均为国内外首次。

汕汕高铁全线建成通车后，将正式进入汕头市区，运能将从目前日均开行24对列车提高到50对以上，并与在建的漳汕高铁连接，在珠三角、海西、长三角之间构筑起一条新南北向大能力客运通道。

文、图 | 记者 赵映光 严锦程 通讯员 林凤 李金雨 张楚宏 盛佳铭 陈梦怡（除署名外）
翻译｜曾敏
审校｜林佳岱