Simplified evaluation of embankment dam health due to ground vibration using dam health index (DHI) approach

In order to execute dam safety planning, it is necessary to develop a method to monitor dam health, which considers and simulates the actual physical failure processes of an embankment dam. The objective of this study is to monitor the behaviour of the earthen dam during the impact of ground force through experimental modal analysis. The model of an earthen dam was constructed on a steel plate, which could be easily moved by input force. Accelerometers were installed on the model in many positions to measure respondent acceleration. The post-processing data were processed to show signs such as natural frequency and mode shape using the least-square complex exponential method. Natural frequency shifts were tracked throughout the testing period and the effects of the varying water levels were identified. During vibration, the effect of liquefaction observed in tests was found to be the first factor to deteriorate on the upstream side of the embankment model. The measurement position of the accelerometer was found to be very important for the health monitoring of the embankment dam. The proposed dam health index is the comparison of acceleration at the crest and the upstream side in both time and frequency domains which can identify damage to the embankment dam.

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