The applicable conditions of dynamic Bouc-Wen model and influence of the model parameters on hysteretic loop

etc. are discussed. Based on the laws of thermodynamics

the incremental dissipation functional expressions of Bouc-Wen dynamic model are formulated. Then the energy dissipation mechanism of damming earth and rocks are analyzed under different levels of dynamic strain; and two threshold strains are found defined as the first threshold strain and the second threshold strain respectively. The corresponding modulus ratios are around 0.94 and between 0.50-0.80. The second threshold strain is equated with the traditional threshold strain using pore water pressure build-up or volume changes as standard. It is good for the further understanding of the dynamic response of soil.