IN SITU INVESTIGATIONS OF DYNAMIC RESPONSE OF EARTH DAM TO NON-UNIFORM KINEMATIC EXCITATION

摘要

The paper presents results of in situ investigations of an earth dam at Czorsztyn-Niedzica to non-uniform kinematic excitation. The excitation was executed by use of a machine exciting harmonic vibrations of optional frequency ranging from 7 to 100 Hz. The machine located on the rocky slope of the valley, close to the dam (in longitudinal axis of the dam), caused vibrations of the subsoil and caused a non-uniform kinematic excitation. Location of the accelerometers was planned so as to make vibration measurements possible in three directions, close to the vibration source on the rocky subsoil and in the control gallery hewn in the rocky subsoil under the dam. Measurement results obtained in these points permitted to determine the wave velocity in the foundation rock. Vibration accelerations were also recorded in selected points of the dam crown for experimental verification of the numerically determined dynamic response. A theoretical model of non-uniform kinematic excitation was proposed. Vibration accelerations were compared in chosen control points: measured during in situ investigations and calculated assuming the proposed kinematic excitation model. Conformability of calculated and measured vibration accelerations gave a positive verification of the calculation model. This model was used for calculations of dynamic responses of the earth dam to a real seismic shock.