Title: Dynamic Finite Element Analysis of Young Shotcrete in Rock Tunnels

Author(s): Anders Ansell

Publication: Structural Journal

Volume: 104

Issue: 1

Appears on pages(s): 84-92

Keywords: dynamic loading; reinforcement; shotcrete

DOI: 10.14359/18436

Date: 1/1/2007

Abstract:
The problem with shotcrete on rock subjected to vibrations has previously been studied in place and through numerical modeling. Within the present project, an elastic finite element model is presented that consists of beam elements used to model the flexural stiffness and mass of the shotcrete lining and a section of rock. Spring elements are added for elastic coupling between shotcrete and rock. The loads on the model are acceleration-time series. Scaling laws for the magnitude of vibration velocities in rock as a function of distance and amount of explosives are used to study the damage to shotcrete at various distances from the source of an explosion. Age-dependent shotcrete material properties are varied to investigate the vulnerability of young shotcrete exposed to explosion-induced vibrations. Recommended minimum shotcrete ages, based on the numerical results, are given for practical use.