Which is better, a tunnel boring machine or a shield machine? In modern tunnel engineering, tunnel boring machines and shield machines are two main tunnel excavation equipment, each playing an irreplaceable role. They have their own characteristics and are suitable for different geological conditions and engineering needs. Therefore, it is not possible to simply say which one is better, but the appropriate equipment should be selected according to the specific engineering situation.
Whether to choose a tunnel boring machine or a shield machine depends mainly on the specific requirements and geological conditions of the project. If the project needs to be carried out under complex and changeable geological conditions and has high requirements for construction speed and safety, TBM may be a better choice. For soft soil projects that require rapid construction and relatively stable geological conditions, shield machines may be more suitable.
The difference between a tunnel boring machine and a shield machine
The tunnel boring machine and the shield machine differ in function, working principle and application scenario.
1. Differences in working principles:
Tunnel Boring Machine (TBM): TBM cuts rock or soil with a rotating cutter head, while using a support system to stabilize the excavation face, and forms a tunnel profile through a continuous advancement process. TBM is suitable for various geological conditions, especially hard rock formations.
Shield Tunneling Machine (Shield TBM): The working principle of the shield machine is similar to that of the TBM, but its unique feature is that it has a movable "shield" structure that provides temporary support during the excavation process, protects the safety of workers and maintains ground stability. Shield machines are particularly suitable for complex geological conditions such as urban underground projects and river crossings.
2. Differences in functional characteristics:
Tunnel Boring Machine: TBM is mainly used for the excavation of straight tunnels, with a high degree of automation and construction efficiency.
Shield Machine: In addition to the functions of TBM, the shield machine can also perform secondary lining operations inside the shield shell, that is, install prefabricated tunnel lining sheets to form the final tunnel structure. Shield machines are usually used in projects that require strong ground stability.
3. Differences in application scenarios:
Tunnel boring machines: TBMs are often used in long-distance, large-diameter railway and highway tunnel construction, as well as in mining and other fields.
Shield machines: Shield machines are mainly used in urban subways, underground passages, river crossings and other projects, especially in densely populated and densely built urban areas. Shield machines can effectively reduce ground subsidence and the impact on the surrounding environment.
Although tunnel boring machines and shield machines are similar in some aspects, such as using rotary cutting to dig tunnels, they have obvious differences in function, working principle and application scenarios. Which equipment to choose depends on the specific engineering needs, geological conditions and construction environment.