Numerical Analyses of Dynamic Responses of an Earth Dam during 1999 Chi-Chi Earthquake in Taiwan

The Pastor and Zienkiewicz (P-Z) model was adopted here as the constitutive model to study the dynamic responses of the Liyutan dam subjected to the Chi-Chi earthquake. For numerical simulation, the shell materials of the earth dam are assumed to satisfy the P-Z model. The optimal material parameters of P-Z model were judged according to the experimental results by Center Region Water Resource Office in Taiwan. Staged construction, seepage, static equilibrium and dynamic response are sequentially analyzed. A comparison is performed between the P-Z model and Mohr-Coulomb model through the dynamic analysis of the Liyutan dam under Chi-Chi earthquake. The influence of permeability of shell on the generation of pore water pressure under earthquake loading was studied. The results show that the large horizontal permanent movements at the upstream shell were resulted and the larger vertical settlement took place at the top of dam after the earthquake. The Mohr-Coulomb model results in higher pore water pressure compared to those obtained of the P-Z model during the earthquake shaking. The pore pressure parameter in upstream shell slightly decreases with the increase of the permeability of shell.