What are the construction methods for tunnel construction projects

Open cut method: suitable for shallow buried tunnels, directly excavate the ground and repair it before filling it back, like digging a ditch.

Underground excavation method: used when buried too deep to excavate the ground, including mining method (drilling and blasting) and shield tunneling method, for underground excavation construction.

Immersed tube method: mainly used for underwater tunnel construction, which involves sinking prefabricated pipe sections to the bottom of the water and splicing them together.

Drilling and blasting method: using a drilling rig to drill holes and blast open rocks, suitable for mountain hard rock tunnels, and supported by the New Austrian Method concept.

Shield tunneling method: using a large shield tunneling machine to drill in soft soil like an earthworm, while digging and installing pipe segments, suitable for urban subways.

Full section method: Explode the entire tunnel outline at once, with high efficiency but requiring hard rock.

Step method: Divide the tunnel into two layers for excavation, with the upper layer being excavated before the lower layer, which is more secure.

CD and CRD methods: Divide the large hole into small holes and excavate them separately, with a partition wall in the middle for support, suitable for weak and fractured strata.

Double side wall guide method: First, excavate the side holes on both sides for support, and then excavate the middle to control deformation effectively.