Abstract:

The precasting of the invert blocks should keep up with the long distance stepping of TBM and the quality of the invert blocks should meet the requirements of the monolithic track beds. Spike embedding technology, invert block overturning technology, invert block temperature control technology and invert block defect prevention/control technology are presented. In the end, low cost, high quality and continuous tunneling are achieved.

Key words: West Qinling Tunnel, precast invert block, embedded spike, overturn in the air, temperature control by means of digital sensor, defect prevention/control 