TBMs are important equipment in modern tunnel engineering, and their classification and application directly affect the efficiency and safety of the project. According to whether they are equipped with shields, TBMs can be divided into open TBMs and shield TBMs. Understanding the characteristics of these two types of TBMs and their application scenarios is of great significance for engineering design and construction.
I. Open TBM
1. Overview
An open TBM is a tunneling equipment without shield protection. It is directly exposed to the environment in front of the excavation face during the excavation process, relying on its own mechanical arm and cutting head to crush rocks and soil, and transport the excavated materials to the ground through a conveying system.
2. Advantages
Wide range of application: Open TBMs are suitable for a variety of geological conditions, especially in stable rock environments.
Low cost: Since there is no shield structure, the manufacturing and maintenance costs are relatively low.
Strong flexibility: The excavation angle and direction can be adjusted according to construction needs to adapt to complex terrain.
3. Disadvantages
Low safety: Since there is no shield protection, the working environment is exposed and may be affected by risks such as landslides.
Poor adaptability: In areas with soft soil or abundant groundwater, the effect of open-type tunnel boring machines is not as good as shield tunnel boring machines.
II. Shield tunnel boring machines
1. Overview
The shield tunnel boring machine has a shield, which protects the environment in front of and around the excavation face during the excavation process, making the excavation process safer and more stable. The mechanical equipment inside the shield is responsible for excavating and transporting materials, while the external structure of the shield provides support to prevent landslides.
2. Advantages
High safety: The shield protects the construction area and reduces the risk of landslides and soil erosion.
Strong adaptability: Especially suitable for use in areas with soft soil, quicksand or abundant groundwater.
Continuous operation: The excavation process can be carried out continuously without frequent shutdown adjustments, and the construction efficiency is high.
3. Disadvantages
High cost: The manufacturing and maintenance costs are high, suitable for large engineering projects.
Poor flexibility: Due to the limitation of the shield structure, the adjustment of the excavation direction and angle is not as flexible as that of an open type TBM.
III. Application scenarios
1. Application of open type TBM
Open TBMs are mainly used in tunnel projects with stable geological conditions, such as mountain road tunnels and mining. They can operate efficiently and safely in these environments, and the maintenance cost is low.
2. Application of shield type TBM
Shield type TBMs are widely used in engineering projects under complex geological conditions such as urban subways, underground integrated pipe corridors, and cross-sea tunnels. Due to their high safety and adaptability, these projects often require the support of shield type TBMs to ensure the smooth progress of construction.
The selection of TBMs is crucial to the success or failure of tunnel projects. Open type TBMs and shield type TBMs have their own advantages and disadvantages, and are suitable for different geological conditions and engineering requirements. Reasonable selection and use of TBMs can not only improve engineering efficiency, but also ensure construction safety. In the future, with the development of technology, the performance and scope of application of TBMs will continue to expand, bringing more possibilities to tunnel projects.