A 3DEC numerical analysis of the interaction between uneven rock surface and shotcrete lining : Validation of physical model and evaluation of influence of unevenness on the support effect of shotcrete

Although shotcrete (sprayed concrete) has been widely used as rock support in mines and in civil engineering projects, the complex interaction between shotcrete and rock has not been studied well. The main reason is that the performance of shotcrete is influenced by a number of important parameters.Experiences from previous research and past projects show that the unevenness of rock surface has a large impact on the number of failures at the interface and in the lining. Furthermore, the behaviour of the lining is sensitive to small amplitudes of the surface roughness. Although people have done some experimental and numerical analysis, the influence of the complex unevenness of three dimensional shaped surfaces on the shotcrete – rock interaction has not been well studied.The project here focuses on the influence of the surface unevenness of a circular opening on the support effect of shotcrete. The work was done by using a 3D numerical simulation (3DEC) and was conducted in two stages. In stage 1, the numerical model was validated by comparing with physical model tests by Chang (1994). In stage 2, based on the well validated numerical model, the influence of unevenness on the support effect of shotcrete was further investigated.Godkänd; 2013; 20121221 (pinzha)