Decoupled seismic analysis of an earth dam

The seismic stability of an earth dam is evaluated via the decoupled displacement analysis using the accelerograms obtained by ground response analysis to compute the earthquake-induced displacements. The response analysis of the dam is carried out under both 1D and 2D conditions, incorporating the non-linear soil behaviour through the equivalent linear method. Ten artificial and five real accelerograms were used as input motions and four different depths were assumed for the bedrock.1D and 2D response analyses were in a fair agreement with the exception of the top third of the dam where only a 2D modelling of the problem could ensure that the acceleration field is properly described. The acceleration amplification ratio obtained in the 2D analyses was equal to about 2 in all the cases considered, consistently with data from real case histories.The maximum permanent displacements computed by the sliding block analysis were small, being less than 10% of the service freeboard; a satisfactory performance of the dam can then be envisaged for any of the seismic scenarios considered in the analyses.     

Evaluation of the seismic response of a homogeneous earth dam

The response of an earth dam to seismic loading is studied through displacement-based analyses and finite element, effective stress dynamic analyses. Displacement-based analyses are carried out using both empirical relationships and the decoupled approach in which the deformable response of the soil is accounted for through ground response analyses, and the resulting accelerograms are used in the sliding block analysis. The FE analyses are carried out using a constitutive model capable to reproduce soil non-linearity, calibrated against laboratory measurements of the stiffness at small strains. The influence of the assumed input motion and bedrock depth on the seismic response of the dam is also studied.     

Use of interaction domains for a displacement-based design of caisson foundations

Acta Geotechnica - Caisson foundations, typically adopted for both onshore and offshore structures, are usually subject to combined loading acting during working conditions and exceptional events...