Research On The Worst Earthquake Input Direction Of Earthrock-Dams

Since the 1960s, more than ten strong earthquakes have happened, and a large amount of earth-rock dams have been destructed. The data of the earthquakes suggest that seismic response is not only related to the the material properties, boundary conditions and geometrical dimension, but also is related to the incident direction of earthquake waves. The incident direction of surficial seismic waves propagated from the deep crust is close to the incident direction perpendicular to the horizontal surface, However, most of earthquakes are shallow seismic source in the world, their incident direction is unsteady. When seismic waves are input from different direction, There will be different seismic response in the structure. Only when the seismic waves are input in a particular direction, can the stress or internal force in the structure achieve maximum. In this case, the seismic incident direction is considered as the most unfavorable incident direction. The paper studies the most unfavorable incident direction for earth-rock. The main contents are as following:Firstly, the paper studies the form of the input of seismic waves. The paper chooses the method of decomposition of inertial force to solve tilt input problem of earthquake waves.Then, the paper analyzes the seismic stability methods comparatively. The paper also studies different input forms of seismic waves, incident direction of seismic waves, and the influence of the height of the dam with the finite element method and nonlinear equivalent stick-elastic models. Through calculation and analysis, the paper gets the most unfavorable direction and the strongest response of position for earth-rock dam under seism load.Finally, the paper takes the zipingpu concrete-faced rockfill dam as an example and verifies the accuracy and applicability of the conclusions.