A 2D roughness method for irregular interface of rock-backfill

A simple and reasonable roughness method for irregular interface of rock-backfill is significant for estimating the long-term stability of mine stopes in underground engineering. In this paper, two new concepts, contribution height difference (CHD) and average contribution height difference (ACHD), were presented through analyzing the influences of whole movement process of asperity and properties of contact material on the shear strength properties of interface. Occupying the presented concepts and combining with the fractal theory, a 2D roughness method for irregular interface of rock-backfill was created, which depends on fractal dimension Dp and direction correlated parameterACHD0. The roughness index Iifwas introduced to quantitatively characterize the roughness of irregular interface. The results of scanning experiment and shear strength experiment about granite and cement backfill were used to verify the proposed 2D roughness method. The application analysis shows that the proposed roughness method has very outstanding advantage for irregular interface of rock-backfill, which provides the evolution of roughness method by involving the directionality of roughness and resolving the effect of sampling interval. The roughness index Iif can predict the shear strength of interface between rock and backfill. The parameters described in this work are easy to measure in field and also they are very convenient in usage.