Understanding the impact of adhesion on the mechanical behavior of shotcrete

Abstract

ABSTRACT Shotcrete is widely used as part of ground support in underground excavations. Although adhesion is recognized as a critical mechanical property of shotcrete, there is no strong consensus from a design perspective on whether high or low adhesion is preferred. This is probably due to our relatively limited understanding of the role of adhesion on the field performance of shotcrete. Laboratory investigations can provide useful insights, but it is difficult to extrapolate to field conditions. Numerical models can complement laboratory investigations, but to develop confidence in their results, they must adequately reproduce the failure mechanism of shotcrete. This paper investigates how different adhesion properties control the mechanical behavior of shotcrete. Laboratory tests were used to calibrate a three-dimensional discrete element method model to capture the adhesion failure of a shotcrete liner. The developed model explicitly reproduced the adhesion failure mechanism, including the load redistribution, loading capacity, and displacement of the shotcrete liner. This was used as a basis for a parametric investigation of the impact of adhesion strength on the mechanical behavior of shotcrete. The numerical results indicated the significant implications in selecting adhesion properties of shotcrete and led to recommendations for adhesion capacity under different ground stress conditions.