Rock construction in hard rock by blasting next to young sprayed concrete is common and needs to be developed with knowledge how the spray concrete is affected by vibrations. The uncertainty about the vibration levels that can be tolerated near freshly sprayed concrete often leads to overly conservative limit values being used in construction, with additional costs and planning uncertainties as a result.
The present report documents a project aimed at proposing practical guidelines for using shotcrete (sprayed concrete) near vibrations.
The focus is on young and hardening wet-sprayed shotcrete for tunnels and civil engineering structures in hard rock and in the vicinity of blasting during the construction phase. The guidelines have been developed through numerical calculations and verified against observations, measurements and in situ results.
At KTH Concrete Structures, the project has been carried out by Anders Ansell (Professor). Appreciated support has been given by a reference group. The reference group consisted of Tommy Ellison (Besab), Rikard Gothäll (Tyréns), Martin Hansson (Sika Sweden), Henrik Ittnér (SKB), Daniel Johansson (LTU), Lars Malmgren (LKAB), Hans-Åke Mattson (ÅF), Mattias Roslin (Swedish Transport Administration) and Per Tengborg (BeFo). The project was financed by the Rock Engineering Research Foundation
(BeFo).
Stockholm, 2019
Per Tengborg