trackless tunneling

例句：

1. 1. The construction of the trackless tunneling project has been completed successfully.
   无轨隧道建设项目已成功完成。
2. 2. The engineers were working on a trackless tunneling project in the city.
   工程师们正在城市中进行一项无轨隧道项目。
3. 3. The trackless tunneling technology is considered to be one of the most advanced in theworld.
   无轨隧道技术被认为是世界上最先进的之一。