Multi-domain equivalent method for prediction of elastic modulus of complex fractured rock mass

Reliable estimation of deformation and failure behaviors of fractured rock mass is important for practical engineering design. This study proposes a multi-domain equivalent method for fracture network to estimate the deformation properties of complex fractured rock mass. It comprehends both the advantages of the discrete fracture network model and the equivalent continuum model to capture the features of discontinuities explicitly while reducing computational intensity. The complex fracture network is stochastically split into a number of subfracture networks according to the domain, length or angle. An analytical solution is derived to infer theoretically the relationship between the elastic moduli of the original complex fractured rock mass and the split subfractured rock masses by introducing a correction term based on the deformation superposition principle. Numerical simulations are conducted to determine the elastic moduli of split subfractured rock masses using universal distinct element code (UDEC), while the elastic modulus of the original model is estimated based on the currently proposed analytical relationship. The results show that the estimation accuracy with the current domain-based splitting model is far superior compared to those with the other two splitting models. Thus, the estimation method of elastic modulus of complex fractured rock mass based on domain splitting mode of fracture network is identified as the multi-domain equivalent method proposed in this paper. The reliability of this method is evaluated, and its high computational efficiency is demonstrated through exemplification with regard to different geometric configurations for stochastically artificial discrete fracture network. The proposed multi-domain equivalent method constructs the theoretical framework except for the regression analysis hypothesis compared to the density-reduced model equivalent method.