The parameters that reflect the excavation performance of TBM (tunnel boring machine) mainly include the following aspects:
1. * * Diameter Range * *: The diameter range of TBM is usually between 2 meters and 10 meters, and the appropriate diameter should be selected according to the scale of the tunnel project and construction requirements. The larger the diameter, the larger the cross-sectional area of the tunnel, and the higher the construction efficiency
2. * * Advance length * *: defined as the distance that TBM advances per unit time, calculated as advance length=excavation speed x time. The influencing factors include excavation speed, working time, tool wear, etc. The importance of advancing the length lies in its impact on the progress and cost of tunnel construction
3. * * cutterhead diameter * *: Defined as the cutterhead diameter of TBM, it refers to the radius length of the cutterhead. The influencing factors are based on the design requirements and construction conditions of the tunnel, and the appropriate cutterhead diameter is selected to meet the engineering requirements. The diameter of the cutterhead determines the excavation capacity and tunnel section size of the TBM. Common specifications include 3 meters, 4 meters, 5 meters, etc. The specific specifications can be selected according to the needs of the project.
4. Material of the cutterhead: The cutterhead material is usually made of high-strength wear-resistant steel, and the connection method of the cutterhead can be welding or bolt connection. In order to improve wear resistance, the surface of the cutterhead is usually sprayed with a wear-resistant coating. The replacement cycle of the cutterhead depends on the wear condition .
5. * * Tool types * *: including disc cutters, shield cutters, scrapers, cutting cutters, and other different types. The selection and configuration of these tools directly affect the excavation efficiency and adaptability of TBM .
6. * * Excavation speed * *: defined as the distance that TBM advances per unit time, influenced by factors such as geological conditions, tool wear, and slag removal efficiency. Optimizing the excavation speed can improve the efficiency and economic benefits of TBM excavation, generally ranging from 30-50m/h, depending on the actual situation of the project .
7. * * Excavation direction control * *: involves the use of measurement systems, guidance systems, and correction systems to ensure that the tunnel axis meets design requirements and improve construction safety .
8. Net excavation rate: This is the main evaluation indicator of TBM construction speed, which is correlated with the physical and mechanical properties of the surrounding rock and TBM excavation parameters. For example, under complex geological conditions, the net excavation rate is negatively or positively correlated with factors such as uniaxial compressive strength, tensile strength, deformation modulus, Poisson's ratio, rock wear resistance CAI value, cutterhead thrust, and cutterhead speed.
The above parameters collectively determine the excavation performance of TBM, and in actual construction, it is necessary to comprehensively consider and optimize these parameters to achieve the best construction effect.
