Experience With Synthetic Fiber Reinforced Initial Shotcrete Lining At The Devil’s Slide Tunnel Projects

Synopsis:

The conventional tunnel design of the Devil’s Slide Tunnel project near San Francisco, California anticipates relatively large deformation in weak rock conditions. To ensure adequate shotcrete initial lining performance, the Contract Documents address the shotcrete flexural strength and its capability to absorb energy post shotcrete section failure using the Round Determinate Panel (RDP) test. To meet the specified requirements of RDP values in excess of 320 joules at 40 mm deflection the Contractor elected to use polypropylene fibers for shotcrete reinforcement. The paper proposes a general overview of shotcrete testing using the RDP test, correlation of deformation performance to rock mass deformation and practical experience with this product, in particular the associated testing.

Experience with Synthetic Fiber Reinforced Initial Shotcrete Lining at the Devil’s Slide Tunnel Project
Proceedings Spritzbeton – Tagung 2009
January 15-16, 2009
Alpbach, Austria