Classification of TBM tunnel

For some time, TBM has been divided into two categories (Grandori, 1996): this kind of TBM is usually used to dig tunnels with limited length in the soft stratum which is basically uniform below the groundwater level with limited pressure. The basic problems faced by this kind of roadheader are cavity, stability of excavation face, urban surface subsidence and so on.

At present, there are two formulations of full-face tunnel boring machine in China, one is rock boring machine (TBM) and the other is shield machine. TBM is a tunnel boring machine suitable for hard rock excavation, and shield machine refers to a tunnel boring machine suitable for soft rock and soil. This statement is somewhat untrue, because now many hard rock TBM also use shield technology, and TBM originally means tunnel boring machine. In view of the confusion of weighing in academic and practice, which has caused a lot of troubles, this paper suggests adopting a unified weighing method in China, and adopting "hard rock TBM" and "soft rock TBM" for standardization (this usage is adopted below). Hard rock TBM can be divided into open cut TBM and shield TBM.

Hard rock TBM is suitable for hard rock excavation of mountain tunnels, replacing the traditional drilling and blasting method. Under the same conditions, its driving speed is about 4 ~ 10 times that of the conventional drilling and blasting method, and the optimal daily footage can reach150m. It has the advantages of high speed, high quality, safety, economy, environmental protection and labor protection. In particular, high efficiency and high speed can make the project completed ahead of schedule and create value ahead of schedule, which is of great significance to China's modernization.

Soft rock TBM is suitable for tunnel boring machine in soft surrounding rock construction, and it is an advanced technology with high speed, good quality and high safety in urban subway construction. The interval tunnel constructed by shield machine can disturb the soft soil, without affecting the ground buildings and traffic, and reduce a large number of demolition on the ground and underground. The technical development and application of these two kinds of equipment have a very broad prospect in the field of underground engineering in China.