Experiments on response of piezometric level to vibrations under hydrostatic condition

This paper explores the response of water-level on the vibrations under hydrostatic condition by carrying on the experiments that put self-designed well-confined aquifer seepage system on the earthquake simulation shaking table. The experiment includes 12 groups of sine vibrations whose frequencies f_in in turns are 0.5, 1, 2, 5, 10, 15 Hz and accelerations a_in are 1.5, 2.5 m/s², respectively. The results indicate: piezometric level presents four kinds of response patterns, that is, ascending, ascending-oscillating, oscillating and descending-oscillating, which are similar with water level variation patterns resulted from earthquakes; among the twelve groups of vibrations, the water level in observation well and pore water pressure were likely to decrease at low frequency (f_in=1, 2 Hz), and increase at mid-high frequency (f_in=5, 10 Hz), oscillate at high frequency (f_in=15 Hz), and the acceleration peak also affects their variation patterns; their variation amplitudes increase first, and then decrease with the increase of input frequency. The maximum amplitude variation respectively appears at the two vibration conditions of a_in=1.5 m/s², f_in=10 Hz and a_in=2.5 m/s², f_in=5 Hz.