Microtunneling is a trenchless technology used for constructing underground tunnels with minimal disruption to the surface and surroundings. It is a cost-effective and efficient method for installing pipelines, cables, and other utilities beneath the surface.
In this article, we will explore the basics of microtunneling, its benefits, and the key planning elements you need to know for a successful microtunneling project.
What Is Microtunneling?: Understanding the Basics
As discussed above, microtunneling is a trenchless method of installing underground utilities without the need for excavation. It involves using a microtunnel boring machine (MTBM) to excavate the soil and rock and create a tunnel to install pipes or utilities. Here’s a closer look at the basics of microtunneling:
- Trenchless Technology: Microtunneling is a trenchless technology that involves minimal surface disruption. Unlike traditional open-cut methods, there is no need for excavation of a trench.
- MTBM: The MTBM is the key piece of equipment used in microtunneling. It is a remote-controlled machine that excavates the soil and rock and creates a tunnel to install pipes or utilities.
- Guided Tunneling: Microtunneling is a guided tunneling technique. The MTBM is guided along the tunnel alignment, which is usually determined by the location of the utility that needs to be installed.
- Slurry System: A slurry system transports the excavated soil and rock to the surface. The slurry system consists of a mixture of water and bentonite circulated throughout the tunnel.
- Jacking Frame: A jacking frame is used to push the MTBM through the ground. The jacking frame provides the necessary force to move the MTBM and the pipes or utilities through the tunnel.
Key Planning Elements of Microtunneling
While microtunneling is a highly popular technology used in construction, proper planning is crucial to ensuring a successful project. Here are the six key planning elements that should be considered:
1. Site Investigation
Site investigation is a critical factor in microtunneling projects. The site investigation involves identifying soil and rock formation, groundwater level, and other geological features that may affect tunneling. A geotechnical investigation report is usually prepared to provide detailed information about the soil and rock properties, groundwater level, and other geological features. This information is used to determine the best tunneling method and equipment.
2. Tunnel Alignment
Tunnel alignment refers to the path that the tunnel will take. The alignment is usually determined by the location of the utility that needs to be installed. The tunnel can be straight or curved, depending on the alignment. The alignment must be carefully planned to avoid obstacles such as existing utilities, buildings, and other structures.
3. Equipment Selection
Microtunneling requires specialized equipment, and equipment selection is crucial to the project’s success. The equipment used will depend on the soil and rock conditions, tunnel diameter, and tunnel length. The equipment used for microtunneling includes a microtunnel boring machine (MTBM), a jacking frame, and a slurry system. The MTBM is used to excavate the soil and rock, while the jacking frame is used to push the MTBM through the ground. The slurry system transports the excavated soil and rock to the surface.
4. Access and Exit Points
Access and exit points are crucial elements of a microtunneling project. The access point is where the microtunneling machine is launched, while the exit point is where the machine emerges from the ground. The access and exit points must be carefully planned to minimize disruption to the surface and surroundings. The access and exit points must also be located in areas that are easily accessible to the microtunneling machine.
5. Contingency Plan
A contingency plan is an essential element of any microtunneling project. The contingency plan should include measures to deal with unexpected events such as equipment breakdowns, soil and rock conditions that differ from those expected, and other unforeseen circumstances. The contingency plan should also include measures to minimize the impact of any disruptions caused by the project.
6. Safety Plan
Safety is a top priority in microtunneling projects. A safety plan should be prepared to ensure that the project is carried out safely and without any accidents. The safety plan should include measures to protect workers, the public, and the environment. The safety plan should also include emergency response procedures in case of accidents or other emergencies.
Benefits of Microtunneling
Microtunneling provides several benefits for a construction project and the people involved, making it an attractive method for installing underground utilities. Some of the benefits of microtunneling include:
- Minimal Disruption: Microtunneling involves minimal disruption to the surface and surroundings, making it an ideal method for urban areas, densely populated areas, and environmentally sensitive areas. The surface disruption can be limited to just the access and exit points, and the excavation can be carried out at a depth sufficient to avoid any surface disturbances.
- Cost-Effective: Microtunneling is cost-effective compared to traditional open-cut methods. It requires less manpower, equipment, and materials and can be completed in a shorter time frame. Additionally, because microtunneling is less disruptive, there are fewer restoration costs associated with the project.
- Accurate Installation: Microtunneling allows for the accurate installation of pipelines, cables, and other utilities. The tunnel alignment can be precisely determined, and the tunnel can be excavated to the exact required diameter. This results in a more accurate installation with less risk of damage to existing utilities.
- Safer for Workers: Microtunneling is generally safer for workers than traditional open-cut methods. Workers are not exposed to the risks of working in a deep trench, and there is less risk of cave-ins and other accidents.
- Environmentally Friendly: Microtunneling is an environmentally friendly method of installing underground utilities. It reduces the amount of excavation required, which results in less soil and rock being transported to landfills. Additionally, it minimizes the environmental impact and reduces the risk of damage to existing structures and trees.
The Importance of Proper Planning in Microtunneling Projects
Microtunneling is a cost-effective and efficient method for installing pipelines, cables, and other utilities beneath the surface. Proper planning is crucial to ensure a successful microtunneling project. By understanding the basics of how it works, its main benefits, and the key planning elements, microtunneling projects can be carried out safely, efficiently, and with minimal disruption to the surface and surroundings.
Technicore Underground Inc. is a vertically integrated group of tunnelling companies headquartered in Newmarket, Ontario, with a major steel fabricating facility in Toronto. We are experienced professionals with technical expertise in every aspect of tunnelling. We’re committed to creating industry-leading innovations and cutting-edge technologies to shape the future of this industry, inspired by more than 30 years of trade knowledge. If you need microtunneling services in Toronto, get in touch with us today!