摘要(英) |
This
research used FLA3D, a numerical analysis software based on the
finite difference method, to analyze the mechanical behaviors of
Pao- Shan in construction stage, and 921 Chi-Chi earthquake.
These numerical results were compared with monitoring identify
the rational of analysis method in this study. From the
numerical results, they are close to the monitoring results and
plane strain (2D) results. Therefore, the numerical analysis is
rational in this study, and it can be so long enough that the 3D
results are close to 2D results. And then the mechanical
behaviors of earth dam were discussed for various ratio of
length and weight of dam and ratio of width and height of core.
In order to identify the safety of the second reservoir of Pao-Shan
under the strong earthquake, 921 Chi-Chi acceleration-time
history was added on the base of the dam. The results show it is
in safety state except for the crust surface on the downstream
of the dam. In the influence evaluation of geometrical
parameters, as the ratio of length and height≧4, the 3D effect
is able to neglect. Natural vibration frequency will reduce with
the length increasing of the dam and the frequency is mainly
about 3Hz. As the ratio of core base-width and height≧0.9, it is
less influential on the deformation. After seepage stage,the
natural frequency is higher than that of before seepage stage.
As the ratio of core increase, the frequency will reduce. As the
ratio of the length and height is equal to 6, and the ratio of
the core base-width is equal to 0.9, the natural frequency
before seepage stage and the third one is after the highest. The
second high one is before seepage stage and the third one is
after earthquake and the smallest one is predominant frequency
of the dam under Chi-Chi earthquake. The natural frequency of
the core is lower than those of crusts on the upstream and
downstream. |