Drilling Machines for Tunnels
Several types of machines are used for drilling tunnels for roads, each catering to specific geological conditions and project requirements. The choice of the tunneling machine depends on factors such as the type of soil or rock, tunnel length, diameter, and construction method. Here are some common types of tunneling machines:
Tunnel Boring Machine (TBM):
TBMs are highly advanced machines designed to bore through various geological formations.
They use a circular cutting head equipped with disc cutters to excavate soil or rock. Simultaneously, the machine installs tunnel linings to support the excavated tunnel.
TBMs are efficient, minimize surface disruption, and are suitable for long tunnels.
Roadheader:
Roadheaders are versatile machines that excavate rock in an open-face tunnel.
Equipped with a rotating cutting head, roadheaders grind or cut through rock, and the excavated material is transported to the surface via a conveyor system.
Suitable for rock tunneling, Roadheaders are adaptable to varying geological conditions and are effective in shorter tunnels.
Drill and Blast Equipment:
This method involves drilling holes into the rock, filling them with explosives, and then blasting the rock to create a tunnel.
Drill rigs are used to create blast holes, and the blasting process fractures the rock, creating a cavity for the tunnel.
Effective in hard rock conditions, but can be more disruptive and time-consuming than mechanized methods.
Microtunneling Machine:
Microtunneling machines are compact, remotely controlled machines used for small-diameter tunneling.
They excavate soil or rock and install precast concrete or steel pipe sections to form the tunnel.
Ideal for urban environments with limited space, and precise control over alignment and grade.
Shield Tunneling Machines:
Shield machines are used in soft ground conditions and are often employed in conjunction with a tunnel lining system.
They consist of a shield structure that supports the tunnel face and houses the excavation equipment. The shield is pushed forward, and the tunnel is excavated within it.
Suitable for soft ground conditions, providing stability during excavation.
Auger Boring Machines:
Auger boring machines are used for the installation of small-diameter tunnels without disturbing the surrounding soil.
They use a rotating auger to bore through the soil, and the excavated material is removed to the surface through the auger flights.
Suited for softer soils, and the process is relatively low-impact.
The choice of tunneling machine depends on factors such as the geological conditions, tunnel length, diameter, and the desired level of surface disruption. Each type of machine has its advantages and limitations, and engineers carefully select the most appropriate technology for the specific tunneling project.