Pushing the Limit—Shallow Cover Slurry TBM Mining Between Active Commuter Rail Tracks

摘要

Slurry TBM evolution has allowed for increased control of face pressure and ground stabilityrnwhich correlates to increased success for shallow cover mining. This was a necessary component of the B/CrnTunnel Extension performed in Queens, NY for the East Side Access Project. Through a coordinated effort, therndesigner, contractor, and construction management teams pushed a 6.86m (22'-6") diameter Herrenknecht slurryrnTBM beyond contract expectations, culminating in less than ½ shield diameter of cover. This paper exploresrnthe operation strategy with details regarding the surface and underground coordination, instrumentation plan,rnand program wide cost and schedule savings associated with its success.