**3.3. Calculation of strain**

As the gauge points are regarded as the nodes, the cross section is discretized with a triangular element. By using the plane strain condition, the shear and volume strains are calculated for each element with the theory of the finite element method.

the number is from 2 to 72, is shown in **Figure 9**. To observe the tendency of the settlement, the displacement is averaged with the period of 0.02 s which is the same as the period of shaking. The downward displacement becomes gradually large with the height of the gauge point. The deformation continues during the experiment at the upper part while the displacement at the lower part does not change so much during the experiment. It is found that the deformation

Seismic Crack Investigation in an Earth Dam by Centrifugal Loading Test

http://dx.doi.org/10.5772/intechopen.78788

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Then, to observe the horizontal deformation, the change in the horizontal distance between two gauge points is investigated. For example, at the upper most part of the dam, the horizontal distance of gauge points 1 and 3 is presented (see **Figure 8**). **Figure 10** shows the change in the horizontal distances at various heights of the dam with time, in which the legend means the number of gauge points used for the distance calculation. While the horizontal distance becomes large at the height of the middle, the number of 29–31, at the early stage, the ones at the upper parts, the number of 1–3 and 5–7, gradually increase with time. The upper parts have a significant change in the horizontal distance finally. Entirely, the center part of the dam

of the upper part occupies the settlement of the dam.

**Figure 8.** Number of gauge points highlighted for observation.

has the horizontal tension behavior except for the lowest part.

**Figure 9.** Downward displacement at the centerline of the dam.
