An investigation of propagation direction induced difference of transmission coefficient in complex rock mass

Complex rock mass (wave impedances on two sides of the joint are different) commonly exists, which results in the propagation direction induced difference of transmission coefficient (PDIDTC). The PDIDTC is defined as the difference ratio of two transmission coefficients of waves in two opposite directions. The present paper further studied the displacement discontinuous method to investigate the PDIDTCs of particle velocity and stress in the complex rock mass. A modified SHPB test was conducted to validate the theoretical results. The effects of incident wave frequency and joint stiffness on the PDIDTC were discussed. Two cases of PDIDTC of blast wave, rectangular pulse and triangular pulse were illustrated. The results show that the PDIDTCs of particle velocity and stress are not influenced by the frequency, joint stiffness and waveform, but are influenced by the wave impedance ratio significantly. Moreover, obvious PDIDTC can be obtained when the wave propagates through complex rock mass, which cannot be ignored during rock dynamic analysis.