Use of centrifuge models to study simulated blast loadings on backfills

CIM Bulletin, Vol. 84, No. 951, 1991

G.N. Nnadi, Strata Engineering Corporation, Kingston, Ontario, and R.J. MitcheD, Queen's University, Kingston, Ontario

The response of cemented backfills subjected to simulated blast loadings is studied using centrifugal modelling techniques. Scaling requirements for centrifugal modelling are developed and the results of the similitude analysis show that an acceleration field is required to capture the true dynamic response of backfill models. Experiments have been conducted at various centrifugal accelerations. The effects of ring blasting were simulated by an impact loading on the exposed fill face. The behaviour of the cemented backfill was monitored with accelerometers as well as dynamic stress gauges. Cemented backfill response to impact loadings was found to depend strongly on simulated gravitational stress level. Results also show that the characteristics of the response changes with distance from the impact. Finally, the results of the models were used to predict prototype peak accelerations, velocities and displacements. The results reported in this study indicate that centrifuge modelling may be a useful tool for dynamic studies of blast damage to backfills. Centrifuge modelling can be carried out at low costs and can be used to design prototype instrumentation systems.

Keywords: Rock mechanics, Backfill, Modelling, Blast loadings, Centrifugal modelling techniques.