Tunnel boring machines (TBMs) are large, specialized machines used to excavate tunnels through various types of soil and rock. They work by rotating a circular cutting head that breaks up the material in front of them, allowing the machine to advance while simultaneously installing tunnel linings. TBMs are commonly used in construction projects for subways, roads, and underground utilities. These machines come in different sizes and designs, depending on the specific project requirements. Some TBMs are equipped with advanced technology to monitor ground conditions and ensure safety. Their use has significantly improved the efficiency and safety of tunnel construction compared to traditional methods.