Tunneling under a concrete slab may seem like a daunting task, but it’s a necessary procedure for many reasons, such as installing utilities or repairing underground pipes. There are several methods for tunneling under a concrete slab, each with its own unique advantages and disadvantages.
Depending on the size and type of the project, different methods may be more suitable. In this article, we will discuss how to tunnel under concrete slab. With the right equipment, techniques, and safety measures in place, tunneling under a concrete slab can be a successful and efficient process.
What Type of Pipe Is under the Slab?
The type of pipe used for tunneling under a concrete slab will depend on the purpose of the tunnel. In most cases, it is necessary to use rigid PVC piping or corrugated flexible piping to create a stable and secure structure. If strength is an important factor, steel pipes are sometimes required.
When installing the pipes, they should be placed in the middle of the slab with appropriate bedding material installed around them. This will help protect against any potential damage caused by settlement and movement beneath the ground surface. Additionally, any connections between pipes should also be well sealed to prevent water from seeping into them and creating structural issues over time.
It is important to ensure that all pipes are laid out according to local building regulations. This will help ensure the safety of anyone using the tunnel and prevent any potential problems in the future. It is also important to make sure that all pipes are properly joined together, as this will provide a stronger overall structure and prevent open ends from creating unpleasant odors or hazardous conditions.
10 Methods How to Tunnel Under Concrete Slab
1. Jackhammering and Hand Digging:
One of the simplest and most straightforward methods of tunneling under a concrete slab is to use a jackhammer and hand dig the tunnel. This method involves breaking up the concrete slab with a jackhammer and then manually excavating the soil underneath. While it’s a labor-intensive process, it’s effective for small projects with limited access.
If you plan to use this method, it’s important to have the right safety equipment and to wear protective clothing. Although this method may seem intimidating, it’s a relatively straightforward process that can be completed in a few hours with the right tools.
2. Soil Displacement:
Another method for tunneling under a concrete slab is soil displacement. This method involves using a hollow tube to push the soil out of the way as it moves through the ground.
The displaced soil is then replaced with a support structure, allowing the tunnel to remain stable. This method is most often used in soft soil conditions since the displaced soil is much easier to replace.
However, it can also be used in areas with harder soil, though the support structure will need to be more substantial. This method requires a relatively small amount of labor and equipment, making it one of the most cost-effective ways to tunnel beneath concrete slabs.
3. Jet Grouting:
Jet grouting is a method that’s often used in soil that’s too hard for conventional tunneling methods. This technique involves injecting a high-pressure flow of water and cements into the soil to create a hardened support structure. The process is complex and requires a specialist contractor with experience in jet grouting.
It can be used to create tunnels that are stable, waterproof and able to withstand the weight of a concrete slab. The process can be costly and time-consuming, but it offers a viable solution for tunneling under concrete slabs in areas where other methods are not practical.
4. Microtunneling:
Microtunneling is a trenchless method of tunneling that involves using a microtunnel boring machine to dig a small-diameter tunnel. This method is often used in areas with limited access and requires less excavation than traditional tunneling methods.
The machine is operated by a remote-control operator from a surface location, and the tunnel is constructed in small sections as it moves along.
This method is relatively safe compared to other tunneling methods and allows for minimal disruption of existing structures or services. Microtunneling can be used to install utility lines, pipelines, and other underground infrastructure under concrete slabs.
5. Pipe Ramming:
Pipe ramming is another trenchless method of tunneling that involves using a pneumatic hammer to drive a steel casing through the soil. This method is often used for installing pipes and cables under roads and railways. The steel casing is pushed forward with the help of a hydraulic ram, and each stroke advances it a few inches.
Once the pipe is in place, it can be filled with concrete to provide a permanent tunnel. This method is relatively quick and causes minimal disruption to the surface, making it an ideal choice for busy roads. It is also easy to adjust the diameter and length of the tunnel, making it suitable for a wide range of projects.
6. Directional Drilling:
Directional drilling is a method of tunneling that involves drilling a curved tunnel underground. This method is often used for installing utility pipes and cables under roads and other obstacles. In order to use directional drilling, first, a pilot hole must be created. This hole is used as a guide for the drill bit and allows the operator to control the direction of the drill when it is pulled back out.
The pilot hole is then widened, and a larger diameter bit is inserted into the opening. This bit is used to create the curved tunnel that will be used for the utility installation. The directional drilling method requires a lot of skill and experience, but when done correctly, it can create a tunnel in the shortest amount of time.
7. Tunnel Boring Machines:
Tunnel boring machines are often used for large-scale tunneling projects. These machines are capable of boring through solid rock and can create tunnels with a diameter of several meters. The machines typically have a rotating cutting head that excavates material from the tunnel face and deposits it behind the machine.
Tunnel boring machines are also capable of installing a concrete lining at the same time as they are boring, which can significantly reduce the amount of manual labor required to complete the tunnel. Tunnel boring machines are often used in construction projects such as those involving the installation of new sewer, water, or power lines.
In addition to tunneling under concrete slabs, they can also be used to create tunnels under roads, rivers and other obstacles.
8. Rock Tunneling:
Rock tunneling involves excavating through solid rock using specialized equipment. This method is often used for mining and constructing large underground facilities. The process requires experienced professionals and specialized tools, and typically involves drilling, blasting, excavating, and installing rock support systems.
Rock tunneling can be a dangerous and expensive process, but it is often necessary for larger projects. Rocks can range from soft sedimentary rock to hard igneous or metamorphic rocks.
The tunneling process for each type of rock requires different methods and equipment, making it important to determine the type of rock before starting the excavation. Special care must be taken when excavating through unstable rocks and hard rocks, as there is an increased risk of cave-ins and other hazards.
9. Cut and Cover:
Cut and cover is a traditional method of tunneling that involves excavating a trench, building the tunnel, and then covering it back up. This method is often used for constructing subway systems and other large-scale infrastructure projects.
To perform a cut and cover operation, the surface must be cleared of any debris, and the area should be leveled. The walls of the trench are then constructed, typically using reinforced concrete.
The tunnel is then built inside the trench and finally it is covered up with soil or other materials. Cut and cover tunneling is a reliable method for constructing tunnels, and can also be used to build access points for utility lines. However, it does come with some disadvantages, including the disruption caused to traffic and businesses during construction.
10. Underground Pneumatic Piercing Tools:
Underground pneumatic piercing tools use compressed air to create a tunnel through soil and other materials. This method is often used for installing utilities and other underground infrastructure in areas with limited access.
It is typically more expensive than other methods of tunneling but can be the quickest and most precise way to tunnel through a concrete slab. The pneumatic tool works by forcing a high-pressure jet of air into the soil or other material, creating a cavity that is then filled with concrete to form the tunnel.
Conclusion
For those looking to tunnel beneath concrete, the process can be complex. To begin, make sure you have the right materials and equipment, as well as a reliable plan of attack. If you don’t feel confident or comfortable taking on this task yourself, make sure to call a professional who can assist you in the project.
You may end up saving time and energy by getting a pro involved. It’s important to remember that knowledge is power – so when it comes to completing this project successfully, information is your greatest ally. With the right approach and an understanding of how to tunnel under concrete slab, you’ll be able to conquer this task with ease. So don’t hesitate any longer – now’s your chance to take charge and do it right!