Fundamental Considerations on the Earthquake Resistant Properties of the Earth Dam. Part I On the Vibration of Earth Dam

The remarkable advance has been achieved in the designing and execution of earth dam in accordance with the development which has been made up to now in the soil engineering. Earth dams as high as 40m have been constructed also in our country. It is often the case that the earth dams above all other kinds of dams may be constructed on the sites where the foundations of earth ground are comparatively weak. Therefore, the dams should be expected to be subjected to large seimic forces, and once they collapse, the failure will cause unforeseen disaster to the downstream region. Accordingly, it is a matter of course that the study on earthquake resistant properties of earth dam is extremely important. This paper discusses, in part I as the first step toward the clearer understanding of earthquake resistant properties of earth dam, the elastic vibration of the two-dimensional dam surrounded by the ground foundation of rectangular boundary, and clarifies the limit of the possibility of treating the problem as the one-dimensional by comparing the above mentioned vibration with that of the one-dimensional dam. In part II, discussions are made on the seismic coefficient to be used for the earthquake resistant design of the two-dimensional earth dam, and a seismic coefficient of design is proposed.