Micro tunneling machine

Types of Micro Tunneling Machines

Micro tunneling machines are classified as per various tunneling methods, applications, design features, and specifications.

• Method of tunneling: The device will be a typical unit of the method it uses for tunneling. For example, in a micro tunneling machine with slurry as a major transport medium, there is an extraction unit for transporting the spoil using the same liquid. In other types of micro tunneling machines with different modes of spoil extraction, there may be an air extraction unit or a conveyor system.
• Soil conditions and rock formation: The device will differ based on its ability to excavate the soil or rock material. For example, in rock formations, a micro tunnel boring machine (MTBM) will be fitted with specific types of cutter heads and disc blades. At the same time, TBMs specialized for soil conditions will have different features for excavation.
• Tunnel size and diameter: Normally, the size and diameter of the micro tunneling machine will depend upon the project requirements and specifications. Usually, they range between 0.5 m to 3.0 m in diameter. The length can be up to 3,000 m. The larger diameter machines are generally used for making sewerage systems and pipelines.
• Control system: The machine may be driven by a computer-controlled system for precise steering and alignment. A typical example of this is a Laser Guidance System. Many micro tunneling machines will have these systems to offer real-time feedback and control of tunnel alignment. A laser-guided system may use theodolites or total stations to monitor and adjust the tunneling direction as per the predefined laser beams. Other types of guidance systems may use GPS or inertial navigation systems.
• Type of pipeline installation: A micro tunneling machine will differ according to the kind of pipeline that has to be laid. For example, one will have a different type of cutter head when laying a sewerage pipeline or an optical fiber cable system.

Specifications and maintenance of micro tunneling machines

Specifications of micro tunneling machines vary depending on the manufacturer and model. The following are key micro tunneling machine specifications:

• The machine's diameter ranges from 1 to 3 meters. Larger machines with more than 3 meters are available, but they use different tunneling methods.
• The length of the micro tunneling machine ranges from 10 to 100 meters. The machine achieves longer lengths with prefabricated segments.
• The maximum gradient of the machine ranges from 1 to 10 percent. The micro tunneling machine works better on small gradients.
• The steel body of the machine is 50 to 100 mm thick. A thicker body stands up to the pressures of hard rock formations.
• There are various types of drives including hydraulic, pneumatic, electric, and robotic drives.
• The machine uses various types of excavation heads for soil, cohesive soil, mixed ground, and hard rock.
• The machine uses different types of pipe jacking systems based on soil conditions and project requirements. Common types include steel pipes, lining rings, concrete pipes, composite pipes, and others.

The micro tunneling machine requires regular maintenance for optimal performance, efficiency, and longevity. The following are some of the most important micro tunneling machine maintenance tips:

• Electrical maintenance: The electrical system should be inspected and maintained. This includes checking the battery, alternator, starter, and electrical connections. The items should be cleaned, tightened, and adjusted as necessary. Routine replacement of the electrical components will prevent electrical failures and downtime.
• Tunnel machine parts: Inspect and maintain micro tunneling machine parts regularly for damage, wear, leaks, and loose or damaged parts. Damaged parts should be repaired or replaced quickly. This helps to improve performance and reduce the risk of breakdowns.
• Lubrication: All moving parts of the micro tunneling machine should be well-lubricated. Lubricate the bearings, axles, chains, and other moving components of the machine. Doing this regularly will reduce wear and tear and prolong service life.
• Hydraulic system: The hydraulic system should be inspected and maintained to ensure it works well. The system's hoses and connections should be checked for leaks, damage, or abrasion. The hydraulic oil level, cleanliness, and quality should be appropriate. Any hydraulic component issues should be addressed promptly to prevent system failures.
• Repair and replacement parts: High-quality repair and replacement parts are vital to the long service life of the micro tunneling machine. This is because high-quality parts meet the exact specifications and standards of the machine.

Scenarios in micro tunneling machines

Microtunneling machines are valuable in various scenarios because they provide accuracy without compromising surface integrity. Here are some applications where microtunneling machines are used.

• Installing Pipes Under Roads and Highways

  Micro tunneling is popularly used for laying pipes under busy infrastructure, like roads and highways. Opening up the ground surface to lay pipes is not only disruptive but also dangerous. Using microtunneling, operators can lay pipes downwards in a straight line without compromising road integrity.

• Water Mains

  Micro tunneling is used to install water mains and other utility lines. Operators can avoid expensive and disruptive surface restoration when they lay water pipes under roads using a micro tunneling machine.

• Railway

  Micro tunneling machines are used for laying pipelines and cables under railways. With these machines, operators can avoid risks associated with train disruptions and ensure stable foundations under railway lines.

• Urban Pipe jacking

  Micro tunneling is a great alternative to open-cut excavation in urban areas. In tight spaces where excavation cannot be possible, micro tunneling machines can be used to lay waterlines, sewers, drainage pipes and other utility lines.

• River Crossings

  Micro tunneling is used for installing pipes across rivers and other water bodies. The method enables the creation of underwater crossings with precise control and minimal environmental disruption.

• Beach and Marine Pipeline

  This method is also used for offshore pipeline projects. Micro tunneling allows for the construction of horizontal tunnels from the shore to offshore platforms or rigs. The tunneling enables the installation of protective casings or conduits for the offshore pipelines.

• Agricultural Drains

  In agriculture, micro tunneling helps install drainage systems or subsurface irrigation. The precise tunneling minimizes soil disturbance and ensures effective drainage or irrigation without damaging existing crops or soil structures.

How to choose micro tunneling machines

There are many options available when it comes to micro tunneling machines. Some key aspects to consider when choosing a micro tunnel boring machine are the project's needs, the machine's capabilities, and any additional features that may be required for efficiency and safety.

The ground condition will largely influence the type of micro tunneling machine chosen. Different types of micro tunneling machines are designed to handle specific types of soil, rock, or ground conditions. For example, a machine with a powerful cutterhead designed for hard rock formations will be used if the project requires boring through rocky soil or bedrock. In areas with unstable soil conditions, a पूरा मिट्टी/जल-वाहन (Soil/Hydraulic Transport) सिस्टम might be necessary to prevent soil erosion and maintain stability.

The diameter and length of the tunnels required for a specific project will also impact the type of micro tunneling machine used. Machines with varying diameter options will be chosen according to the specifications. The length of the tunnel also affects the choice of machine, as longer-distance tunneling projects may require different types of power units or additional segment assembly units for efficient operation.

When it comes to efficiency and safety, the machine's additional features will also be an important consideration. This includes features like the type of cutterhead (class type, number of bits, and size), the muck removal system (soil/hydraulic transport system), type of drive unit (electric, diesel, or hydraulic), and assembly/disassembly system. Depending on specific project requirements, it may be necessary to choose a micro tunneling machine with specific configurations or additional assembly units to ensure a smooth tunneling operation.

In addition to the features of the micro tunneling machine, the following aspects of the project must also be considered: the site's logistical constraints, the protection of the surface environment, the underground structures, and the budget of the project. In situations where the surface environment needs to be protected, for instance, a cross section thrust-bore method may be more cost effective than conventional micro tunneling. An expert's insight may be required to choose the most appropriate type of machine according to other tunneling methods and the project's budget. In some cases, it may also be possible to economize by choosing a machine that is capable of handling various tasks, such as a combination of milling and tunneling.

Micro tunneling machine Q & A

Q1: How large is a micro tunneling machine boring?

A1: The diameter of micro tunneling machines is typically between 0.6 and 2.4 meters. They also have the flexibility to construct tunnels of varying diameters depending on project requirements.

Q2: How long does a micro tunneling machine take to complete a tunnel?

A2: Micro tunneling speed varies based on several factors, such as the tunnel length, diameter, soil conditions, machine size, and project complexity. In favorable conditions, the micro tunneling machine can advance at a rate of approximately 1 to 3 meters per hour.

Q3: Does a micro tunneling machine have an air conditioning system?

A3: Yes, There is a need for climate control inside the micro tunneling machine. Therefore, the machine may have some sort of air conditioning system. This may be a portable evaporative air conditioner or a dehumidifier.

Q4: How much power does a micro tunneling machine use?

A4: The power requirements for micro tunneling machines vary depending on their size, type, and specific tunneling conditions. But in general, the power consumption of micro tunneling machines is usually between 300 to 1,000 kilowatts.