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This paper presents modeling of rock spalling induced by a dynamic pulse using the finite-discrete element method, for the purpose of tunnel support design to withstand blasting. 1D and 2D model results are compared to analytical spalling equations and field test findings. It was found that only the 2D models are suitable for support design. A distinction between heavy spalling and light rockfall is made based on an estimation of the ratio of the peak stress of the arriving wave to the rock tensile strength. Accordingly, different design approaches are suggested: for heavy spalling a low impedance isolating layer between the tunnel liner and surrounding rock is recommended. For light rockfall, a simplified static FEM analysis procedure is presented. [ABSTRACT FROM AUTHOR]

• Fiber reinforced concrete slabs were tested under close-in and contact detonations. • The damage and response modes were recorded. • Fiber reinforcement was found to be effective only for the contact detonations. • Close-in detonations were manifested by a global response. • Available empirical tools need to be improved to consider the concrete mix parameters. This paper presents an experimental research to study the behavior of fiber-reinforced concrete slabs with varying fiber volume and type, subjected to contact and close-in detonations. A total of 25 full-scale blast tests were carried out. The results are analyzed, discussed and compared to fast-running tools. For the close-in detonations, the damage was manifested by a global flexural response and the fiber volume did not affect slab performance. For the contact blasts, localized damage in the forms of cratering, spalling, and in some cases perforation, was observed. For these tests, increasing fiber volume was found to improve slab performance. [ABSTRACT FROM AUTHOR]