MICROTUNNELING
MICROTUNNELING
Microtunneling is a trenchless construction technique that uses specialized machinery to excavate precise underground tunnels in a variety of ground conditions, including silt, clay, incohesive soils, gravel, and rock.
The Tunneling Company’s experienced crews and innovative equipment provide microtunneling services to clients across North America. They cover all scopes of trenchless work, including shaft construction, and can advise on the best commercial and technical fit for your project.
CAPABILITIES
Microtunneling uses slurry tunneling techniques that can be executed in almost all ground conditions, including highly permeable areas with high water pressures. This methodology provides additional environmental and safety benefits, helping organizations meet key sustainability standards.
Microtunneling allows for tunneling alignments with small radii curves by utilizing advanced guidance systems, Intermediate Jacking Stations (IJS), and project-specific pipe design. The ability to apply a radial overcut to the product pipe — and by extension, the ability to pump lubrication into the annulus — helps alleviate friction and reduce pressure. Microtunneling also provides tunnel access in diameters greater than 1200mm ID, making it possible to inspect and remove obstructions.
APPLICATIONS
MICROTUNNELING BORING MACHINES (MTBMS)
Microtunnel Boring Machines (MTBMs) are closed-faced machines with hydraulic closed slurry circuits, which convey excavated material from the tunnel face to the surface. They can operate in ground conditions ranging from silt to gravel and rock, with a range of cutterheads available to maximize efficiencies while tunneling.
Excavated material moves through the cone crusher, then is pumped through the slurry line and out of the drilling pit. The water and solids pumped through the slurry line are separated in the above ground separation system. Then, the water is recycled through the system for further use, creating a ‘closed circuit system.’ This feature reduces waste, and maximizes efficiency.
MTBMs are also able to provide detailed feedback to the remote operator, including horizontal and vertical position, yaw, roll, and projected position — helping them steer with a high degree of accuracy.
ADVANTAGES
1. Construction
- Effective in various soil and geological conditions, including soft soil, clay, sand, and rock above or below the water table.
- Allows for precise alignment and grade control, making it suitable for projects with tight tolerances or in congested urban areas.
- Suitable for shallow crossings, water crossings, and crossings near critical infrastructure.
- Completes long-distance crossings without the need for intermediate shafts.
- Mitigates many significant worker safety hazards due to its use of remote-operated tunneling technology.
2. Environment
- Helps preserve natural habitats and reduces risk of soil contamination by avoiding extensive open cut trenches.
- Produces less noise and vibration than other trenchless technologies, reducing impacts on surrounding communities and wildlife.
- Uses less fluids compared to Horizontal Directional Drilling due to its water recycling system.
3. Community
- Minimizes the disruption to roads, buildings, and other infrastructure by reducing the need for extensive excavation.
- Reduces the risks associated with trenchless crossings in close proximity to existing services.
- Reduces site footprint, making it easier to work in tight urban environments.
SHAFT CONSTRUCTION
Microtunneling projects often require a shaft to reach the required depth before tunneling begins. These range from launch and reception shafts to large-diameter tank solutions, with the method of installation depending on specific project requirements and geotechnical conditions. The Tunneling Company designs and constructs shafts for temporary and permanent work solutions. Our versatile team and fleet allow us to combine different shaft installation methodologies, providing the most cost effective solution for our clients.
Shaft Specifications:
- Any depth, as permitted by ground conditions. TTC can utilize shaft sinking to complete installations below the water table.
- Internal diameters ranging from 1.2 – 30 m.
- Can accommodate small site boundaries and rights of way as needed.
Methodologies:
- Segmental Caisson (Jacked and Underpinning Solutions)
- Cast Insitu Caisson
- Sheet Piles
- Secant Piles
