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Abstract In order to study the transmission law of P-wave across the dual nonlinear elastic rock medium with one set of joints，numbers of imaginary joints with small spacing and large stiffness were set in spatial domain. The nonlinear deformation BB model of rock joint was applied to certain joint location. Combined with the characteristics line equation of nonlinear wave，the time-domain numerical solution of transmitted wave from one-dimensional P-wave across rock with various numbers of joints was obtained. The computational program with finite difference method was developed. Then，the program was validated by using previous computation result；and the parameters were further discussed through simulation. The relationships between the parameters of P-wave and joints，joint number，joint spacing，the nonlinear coefficient of rock and waveforms of the first wave and the follow-up wave，transmission coefficient of the first wave，energies of the first wave and the follow-up wave were investigated. The study results show that when the transmission distance increases，P-waveforms distortion with larger amplitude and lower frequency occurs，while P-waves with small amplitude and low frequency are not sensitive to the nonlinear interaction of rock. Transmission coefficient of the first wave，energies of the first wave and the follow-up wave are influenced by joint spacing and nonlinearity coefficient of rock. When P-waves with small amplitude and high frequency cross the large number of joints，the joints showed the role of high frequency filtering and energy decomposition.
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Received: 14 June 2012
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2012, Vol. 31 
