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A DFN–DEM Multi‑scale Modeling Approach for Simulating Tunnel Excavation Response in Jointed Rock Masses

AUTHORS: Xin Wang and Ming Cai

ABSTRACT: Based on the concept of the representative elementary volume (REV) and the synthetic rock mass (SRM) modeling technique, a DFN–DEM multi-scale modeling approach is proposed for modeling excavation responses in jointed rock masses. Discrete fracture networks (DFNs) are generated using MoFrac. For a given volume of jointed rock masses, multi-scale DFN models are constructed according to the hierarchical order of fracture size. Based on the DFN models of various scales, equivalent rock mass properties are obtained using 3DEC SRM models. A tunnel excavation simulation using data from the Äspö TAS08 tunnel is conducted to demonstrate the applicability of the proposed multi-scale modeling approach. The modeling results show that it is efficient to model the mechanical response of the rock mass using the proposed approach. The proposed approach has the advantages of both equivalent continuum and discontinuum methods, with a higher degree of accuracy compared with the pure continuum approach and a less computational effort compared with the pure discontinuum approach.

KEYWORDS: Multi-scale approach, Jointed rock mass, Discrete fracture network modeling, Synthetic rock mass, Representative elementary volume, Äspö TAS08 tunnel

CITATION: Wang, X., Cai, M. A DFN–DEM Multi-scale Modeling Approach for Simulating Tunnel Excavation Response in Jointed Rock Masses. Rock Mech Rock Eng 53, 1053–1077 (2020). https://doi.org/10.1007/s00603-019-01957-8