Research And Numerical Simulation Of Dams Damaged In Wenchuan Earthquake

Earth-rock dam is widely used type for its easily obtained material, easy construction and more over, strong ability to conquer basement's deformation. Large portion of earth-rock dams are erected in west area of our country where earthquake frequently threaten the safety of dams. To take the Wenchuan earthquake for an example case, 2666 dams distributed in eight provinces or counties suffered damage of varying degree. So, analyzing the cause of seismic damage, and to improve the seismic capability of dams, is significant both theoretically and practically. This study did a detailed statistical analysis of information about dams damaged in Wenchuan earthquake , summarized the geographic diversity and features of dams'seismic hazard .This study also choosed Maweihe dam with typical seismic hazard and simulated its collapse under earthquake using software FLAC. Main work are included in following.1. Systematically summarizing the historical researches and current status of research of stable analysis of earth-rock dams, during which several common methods of analysis are comprehensively studied and discussed. Accordingly, advantages and drawbacks of these methods are summarized completely, and direction of development in future for stable analysis of earth-rock dam is also analysised.2. After systematically studied and analyzed information about seismic damage of earth-rock dam in Sichuan province during Wenchuan earthquake, distribution relationship of earth-rock dams'damage and fault direction, magnitude are given. We systematically analyzed type of damage for earth-rock dam, and found out that main damage type which would lead to dam collapse is dam slip.3. Briefly introducing the finite difference method and Mohr-Coulomb model. Interpreting how the complete non-linear method is implemented in FLAC. Then the question of what kind of border should be adopted in dynamic analysis is put forward, and the theory and application of glutinous border and free border are introduced. The conclusion in this study points out that, to geotechnical structures like the earth-rock dam, dynamic analysis of such structures should adopt glutinous border for bottom border and free border for lateral border to model accurately the real situation.4. Taking the Maweihe dam which almost broke in Wenchuan earthquake as an example, this study makes a dynamic stable analysis of the dam using software FLAC. And mechanism of slide and lateral crack is modeled as well.