Effects of Shear Modulus Evaluation Method for Unsaturated Area to Earth Dam's Response Acceleration
2021 Volume 31 Issue 1 Pages 40-52
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2021 Volume 31 Issue 1 Pages 40-52
Seismic response analyses for an ideal earth dam model were conducted by equivalent linearizing method in order to investigate the effects of evaluation method for shear modulus of unsaturated area to the response acceleration. The G-γ (correlationship between shear modulus and shear strain) for the analyses were obtained from soil tests at saturated and unsaturated conditions. Input waves with maximum acceleration of 0.5 m/s2 and 5.0 m/s2 derived from the observed data at Kawanishi Dam were applied. Today's standard method, which calculated the shear modulus at unsaturated condition by multiplying the shear modulus at saturated one for every shear strain by the ratio of the initial shear modulus at unsaturated condition to that at saturated one, tended to estimate the shear modulus at unsaturated condition to be larger in the specific range of shear strain and the response acceleration to be smaller in most part of the unsaturated area than the method which reproduced the G-γ obtained from soil tests.
