Specifying Design-Builder’s Pressurized-Face Soft Ground Tunnel Boring Machines—Learning from the Past and Moving Forward,from Designer’s Perspectives

摘要

Pressurized-face Tunnel Boring Machines (TBM) are in high demand in urban areas in NorthrnAmerica and internationally. Recent technology innovations, such as new conditioning admixtures, remoternsensing/monitoring, advanced probing and grouting techniques, have enabled the construction of large diameterrntunnels in shallow ground cover and difficult subsurface conditions with minimal ground loss. This is evidentrnfrom a wide range of recent literature on pressurized-face tunneling projects. This paper provides a comparisonrnof over 40 such tunnels based on their dimension, machine features, geological setting, ground loss, and groundrnimprovement performed. Based on recent design-build tunnel experience, recommendations are presented forrnbest practices in specifying soft ground TBMs to maximize performance and reduce risk.