Building a tunnel is an in-depth process requiring construction company owners and general contractors to assess several aspects of the project and its surroundings. For instance, you’ll need to evaluate the type of ground that the tunnel is being built on (soft ground, hard rock,  soft rock, subaqueous) before construction begins.

That being said, the procedures involved in constructing a tunnel are relatively consistent. These processes include the following:

• Investigation
• Excavation
• Material transportation
• Ground support
• Environmental control

The average person is unaware of how many intricate components are required to build a tunnel, regardless of its location. Although the exact components may vary based on your project, standard tunnels require the following components:

• Soil
• Segment lining with support measures
• Tunnel boring machine (TBM) with hydraulic jacks
• Grouting

If you plan on working on an urban tunnel (in a city or large town), you’ll also need to keep the current infrastructure in mind.

Construction company owners need to address a handful of challenges before and during the tunnel construction process. One of the main challenges is geological variability, which refers to the variance of the consistency of the soil/rock on which the tunnel is being constructed. For instance, if the soil/rock is softer than expected, your team will need to adjust their processes.

Groundwater is another common issue construction company owners face during tunnel construction. Project stakeholders need to clearly identify all sources of groundwater (prior to construction) to prevent groundwater from potentially hindering operations.

Constructing a tunnel in an urban area is quite challenging for even the best construction company owners. This is due to the fact that there are several challenges and hurdles that need to be addressed before and during the construction process. Some of the most common challenges of building a tunnel in an urban area include:

• Shallow cover
• Difficult soil conditions
• Groundwater infiltration
• Proximity to sensitive structures (ex. historic buildings)