**5.1. Conditions**

To investigate the reproducibility of the extension strain distribution by numerical simulation, the dam model of which size is the same as the 1-G shaking test [2] is simulated. In this study, two cases are examined. The first one is the case in which the dam body is directly shaken at the bottom of the dam. The second one is the case in which the thin base is added under the dam. The objective of the second case is to input the inhomogeneous wave into the dam body. When a given wave is subjected to the bottom of the base, the shaking of the bottom of the dam body becomes a little inhomogeneous, while the amplitude is not so different. The dam body has a height of 150 mm and upstream and downstream gradients of 1:0.545. As the slope gradient is steep, the shaking would be intensified at the upper part.

To examine the strain distributions, the elasto-plastic finite element method (FEM) using Mohr-Coulomb's criteria as the yield function is applied in this study. The bottoms of the models are subjected to 2.4 Hz of a horizontal sine wave. The amplitude is 280 gal.

**Figure 16** shows the schematic view of the models and **Table 1** indicates the material properties. By setting the elastic modulus of the base a little smaller than that of the dam, the shaking situation at the bottom of dam body becomes inhomogeneous by the different behavior of reflected wave depending on the location.
