June 7-10, 2009
Fibre Reinforced Shotcrete (FRS) is now used together with bolts for ground support in almost every underground metalliferous mine in Australia. Safety and economy have been the primary factors driving the widespread adoption of this system of ground support. Thickness, strength, and toughness requirements for long-term stabilization of hard rock ground are relatively well understood for the majority of ground conditions, but minimum safe re-entry times following spraying remain unclear. This issue has therefore been addressed through a series of experimental and theoretical investigations that have assessed common ground conditions in metalliferous mines and compared this to the local load capacity of a freshly sprayed FRS lining. The result is a tentative indication of minimum shotcrete strength requirements before safe re-entry is possible.
E. Stefan Bernard, "EARLY-AGE RE-ENTRY UNDER FRESH FIBRE REINFORCED SHOTCRETE" in "Shotcrete for Underground Support XI", Felix Amberg, M.o.S. ETHZ, SIA, Switzerland; Knut F Garshol, BASF Construction Chemicals, LLF, USA Eds, ECI Symposium Series, (2009). http://dc.engconfintl.org/shotcrete/6