Abstract:

When a tunnel is built by hardrock TBM, there is a prominent feature that TBM and D&B (drill and blast) are used in the same tunnel. Therefore, stepping of TBM, even longdistance stepping of TBM, has to be made before TBM driving, during site changing of TBM, or after TBM driving. TBM stepping speed will significantly affect the construction period for a project. In the paper, the existing TBM stepping techniques are systematically summarized, and the slidingtype TBM stepping technology, which has been widely applied due to its high efficiency, are presented. The technologies presented include the structure and principle of the slidingtype TBM stepping technology, the stepping process, the main technical points, the application result, the adaptability improvement, and supplementary facilities to which special attention should be paid. Slidingtype TBM stepping technology has many advantages, such as less equipment investment and facility investment, high stepping speed, and being suitable for both longdistance stepping and shortdistance stepping. 

Key words: opentype hard rock tunnel boring machine (TBM), stepping technology, stepping mode, sliding plate