Abstract
Japan is one of the most earthquake-prone countries in the world. Many structures suffered from the great damage in the past. Fortunately any gravity-type concrete dam did not collapse and was not a disaster for the downstream area. However, some damages of the dam body were reported after the earthquake. The most one is the increase of leakage from dam, which accounts 60% of the total damages. The gravity-type dam has many longitudinal and lateral joints in the body. The increase of leakage might be cased from broadened aperture of the joints. In this study, the behavior of the joints in the dam body is examined with the 3-D numerical model by the input waves having the different directions. It is found that the lateral joints at the maximum cross section have the broadened aperture when the wave is inputted from the axial direction, and that the lateral and longitudinal joins near the abutment behave to increase the leakage when the wave is inputted from the up and down-stream direction.
