NUMERICAL MANIFOLD METHOD (NMM) SIMULATION OF STRESS WAVE PROPAGATION THROUGH FRACTURED ROCK MASS

Abstract

The present work is devoted to the simulation of stress wave propagation through fractured elastic media, such as rock mass, by using the numerical manifold method (NMM). A single fracture is used to verify the capability and accuracy of the NMM in modeling fractured rock mass. The frequency-dependence on stress wave transmission across a fracture is analyzed. The influence of the fracture specific stiffness on the wave attenuation and effective wave velocity is discussed. The results from the NMM have a good agreement with those obtained from a theoretical displacement discontinuity method (DDM). Taking the advantage that the NMM is able to simulate highly fractured elastic media with a consistent mathematical cover system, a numerical example of stress wave propagation through a fractured rock mass with numerous inherent fractures is presented. It is showed that the results are reasonable and the NMM has a high efficiency in simulating stress wave propagation through highly fractured rock mass. A safety assessment of a tunnel under blast is conducted by using the NMM subsequently. The potential application of the NMM to a more complex fractured rock mass is demonstrated.