A tunnel boring machine (TBM) is a large, specialized piece of equipment used to excavate tunnels through various types of soil and rock. It operates by rotating a circular cutter head that breaks up the material in front of it, allowing the machine to advance forward. As it moves, the TBM installs segments of tunnel lining to support the newly created tunnel. TBMs are commonly used in construction projects, such as subway systems, road tunnels, and water pipelines. They are designed to minimize surface disruption and can operate in challenging environments, making them essential for modern underground construction.