Tunnelling is a critical
aspect of modern construction, playing a vital role in the development of
infrastructure such as subways, highways, railways and utility networks. The
evolution of tunnelling techniques and the introduction of advanced machinery have
transformed the industry, enabling the construction of longer, deeper, and more
complex tunnels at faster pace.
Traditional tunnelling
methods are labour-intensive and fraught with risks. Workers faced hazardous
conditions, including the potential for collapses, exposure to toxic gases, and
limited ventilation. The use of explosives, while effective in breaking through
rock, also pose significant dangers, requiring careful handling and precise
timing to avoid catastrophic accidents.
In contrast, modern
tunnelling methods and equipment emphasize safety, efficiency, and precision.
The advent of tunnel excavation and boring machines, and advancements in ground
support and stabilization techniques and equipment together with proper
ventilation and air quality management systems, and sophisticated safety
monitoring and control systems not only enhance the efficiency and feasibility
of tunnelling projects but also significantly improve safety outcomes for
construction workers and surrounding communities.
Core
Machines That Shape Tunnels
Building tunnels through
rock and soil requires powerful machines designed for precision and
adaptability.
Tunnel
boring machines (TBMs): Tunnel boring machines create tunnels with a
circular cross-section by using a rotating cutting head to grind through hard
rock and soil. As they move forward, conveyor systems remove excavated
material, keeping the construction site efficient.
Drill
jumbos: Drill jumbos are specialists in accuracy. Equipped with
multiple booms, they drill precise patterns into hard rock, often for
explosives or installing rock bolts. They also play a key role in preparing
tunnel walls for reinforcement, which makes them essential for projects
requiring stability and safety.
Roadheaders:
Roadheaders are increasingly popular in tunnel construction for their
flexibility, mobility, and eco-friendly design. With adjustable cutting heads,
booms, hydraulic systems, and conveyors, they handle various tunnel sizes,
shapes, and openings with ease.
Equipment
for Ground Support and Stabilization
Effective ground support
and stabilization are crucial for maintaining tunnel integrity and safety.
Various equipment and techniques are employed to reinforce the tunnel structure
and prevent collapses, including:
Shotcrete
Machines: These machines apply a layer of concrete to the tunnel
walls, providing immediate structural support.
Rock
Bolting Systems: Bolts are driven into the rock or soil to
stabilize the ground around the tunnel. These systems can be automated for increased
efficiency and safety.
Steel
Ribs and Lattice Girders: These structural elements provide additional
support, especially in areas with unstable ground conditions.
Grouting
Equipment: Grouting involves injecting a mixture of cement and
water into the ground to fill voids and strengthen the soil or rock.
Ventilation
and Air Quality Management Systems
Maintaining proper
ventilation and air quality is critical in tunnel construction to ensure a safe
working environment. Modern tunnelling projects employ advanced ventilation
systems to provide fresh air, remove dust and gases, and control the
temperature. Key components of these systems include:
Ventilation
Fans: High-capacity fans that circulate fresh air through the
tunnel and extract contaminated air.
Ducting
Systems: Flexible or rigid ducts that distribute air throughout
the tunnel.
Air
Quality Monitors: Sensors that continuously measure levels of
dust, gases, and other pollutants to ensure compliance with safety standards.
Safety
Monitoring and Control Systems
Modern tunnelling projects
are equipped with sophisticated safety monitoring and control systems to manage
risks and respond to emergencies. These systems include:
Geotechnical
Instrumentation: Instruments such as inclinometers,
piezometers, and strain gauges monitor ground movement and stress levels in
real-time.
Environmental
Monitoring: Sensors that detect hazardous gases, water
ingress, and other environmental hazards.
Control
Rooms: Centralized locations where data from various monitoring
systems are analyzed, and decisions are made regarding tunnel operations.
Emergency
Response Systems: Protocols and equipment, such as fire
suppression systems and escape routes, designed to protect workers in case of
an emergency.
