Tool shape and its function The shape of the tool must adapt to the characteristics of the construction geology, and the tool has different functions and requirements at different positions on the cutting section, so the tool should be designed.

①The cutting efficiency of the tool in sand, sand and pebble formations, that is, how to reduce cutting resistance and ensure the fluidity of the cutting soil.

② By changing the shape of the tool, the excavation wear of the tool is reduced and the durability of the tool is improved.

③ Adapt to the needs of construction in bustling urban areas and minimize the interference to the surrounding soil and environment during the soil cutting process of the cutterhead rotating tool, such as vibration, noise, etc.

④ How to put forward practical measures from the aspects of materials and design to solve the problem of tool wear (including impact and falling blocks, etc.) when the shield machine is tunneling in sand and gravel strata, so as to ensure the reliability of the shield machine's tools for long-distance excavation.