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The secret weapon of underground exploration: How does a tunnel boring machine work?
Tunnel Boring Machine (TBM), also known as "gopher" or "bug", is a mechanical device specially used for digging tunnels. These tunnels can pass through solid rock, wet or dry soil, and even sand. Tunnel boring machines are designed differently as each geological condition requires appropriate technology. Compared with traditional drilling and blasting methods and manual excavation, TBM can more effectively reduce the disturbance to the surrounding soil, and the resulting tunnel wall is smoother, which not only reduces the structural cost inside the tunnel, but also makes it more suitable for use in urban areas. construction is more suitable.
Tunnel boring machines have revolutionized the efficiency and methods of tunnel construction with their excavation speeds of up to 700 meters per week.
The working method of a tunnel boring machine can be divided into several main parts, including the cutting head at the front end, the main bearing, the propulsion system, the excavation material removal system and the support mechanism. Depending on the geological conditions of the site, the presence of groundwater and other factors, the design and operation mode of the machine will vary. It is worth noting that the excavation speed of tunnel boring machines has increased significantly with the evolution of history, rising from 4 meters per week in the 19th century to up to 700 meters in the 21st century. This is a clear manifestation of technological progress.
The history of tunnel boring machines
As demand for tunneling technology continues to rise, tunnel boring machines have a long history. The earliest tunneling-related inventions can be traced back to the 1800s. The tunnel shield designed by British Sir Mark Elizabeth Brunel in 1825 was the earliest tunneling tool. However, tunnel boring machines in the true sense continue to evolve over time and as technology advances.
"Tunnel boring machines are not only a major advancement in the industry, but also the key to changing urban underground construction."
In the mid-19th century, Henri Maus designed the first reported tunnel boring machine, but it wasn't until the 20th century that these technologies really started to come into play. A machine invented by an American engineer in 1912 was used to dig the Hoosac Tunnel in the northwestern United States, marking an important milestone for tunnel boring machines.
Types of tunnel boring machines
Today's tunnel boring machines can be divided into many types based on different geological characteristics and excavation requirements, the most basic of which include shield TBM and main beam TBM. Shield-type TBMs are usually used to excavate in the soil and install concrete sections behind them to support the tunnel walls; main-beam TBMs do not install these concrete sections, but use ground support technology to maintain stability.
"Each TBM design corresponds to specific geological conditions, making the excavation process more efficient and safer."
In addition, what distinguishes tunnel boring machines are the differences in opening surfaces and compression resistance methods. For example, the open soft soil TBM is designed for low-strength soil and can be used when the space created by excavation does not require immediate support. Next work. The diverse designs of tunnel boring machines reflect the need to continuously adapt to different construction requirements and environments.
Urban and near-surface tunnel construction
When using tunneling technology in cities, it is particularly necessary to consider the issue of undisturbed ground and soil settlement. This requires the tunnel boring machine to maintain soil pressure during construction, which is usually achieved through the use of frontally controlled TBMs. These TBMs can effectively reduce the risk of surface settlement and void formation.
Whether it is excavating subway tunnels, railway tunnels or other urban infrastructure, tunnel boring machines play a vital role in underground engineering. As technology advances, future tunnel boring machines will be more efficient and able to adapt to more complex geological environments.
Among the evolution of many tunnel boring technologies, which technology can best meet the challenges of future urban infrastructure construction?
