DOI: 10.5061/dryad.c59zw3r51
title: Water level response in wells to dynamic shaking in confining unconsolidated sediments: a laboratory study

description: This article focuses on laboratory experiments designed to investigate the
 influence of dynamic shaking on water level fluctuation in wells of
 unconsolidated sediments. A large flume filled with natural sandy
 sediments was subjected to horizontal dynamic loading at different
 frequencies (0.5-15Hz) and accelerations (0.1g, 0.15g, 0.25g and
 0.5g), generated by a shaking table. Thus, the change in
 characteristics of the water and saturated sediments were investigated,
 including how water level and hydraulic properties
 changed over time, are of
 significant interest. A range of water level
 changes following the oscillating pore pressure for hydrostatic
 and hydrodynamic (flowing) conditions
 were observed: oscillation, step-rise, step-rise with
 oscillation, and step-drop with oscillation, similar to those observed in
 nature after earthquakes. We find that water level
 declines occur when the imposed frequency is less than 2Hz, while the
 acceleration has weak correlation on the water level change when it is
 less than 0.5g. Sinusoidal wave propagation reduces hydraulic conductivity
 first sharply which then stabilizes at a constant value with a slight
 increase.  Heterogeneous consolidation, mechanical
 resonance, compaction, dilation, and re-packing of the grain
 structure may constitute a physically plausible mechanism for
 water level fluctuations and hydraulic parameters adjustment.
 Laboratory experiments can therefore provide quantitative and
 process-oriented approach to better understand water level
 response to seismic waves.This article focuses on laboratory experiments
 designed to investigate the influence of dynamic shaking on water level
 fluctuation in wells of unconsolidated sediments. A large flume filled
 with natural sandy sediments was subjected to horizontal dynamic loading
 at different frequencies (0.5-15Hz) and accelerations (0.1g,
 0.15g, 0.25g and 0.5g), generated by a shaking table.
 Thus, the change in characteristics of the water and saturated sediments
 were investigated, including how water level and
 hydraulic properties changed over time, are of
 significant interest. A range of water level
 changes following the oscillating pore pressure for hydrostatic
 and hydrodynamic (flowing) conditions
 were observed: oscillation, step-rise, step-rise with
 oscillation, and step-drop with oscillation, similar to those observed in
 nature after earthquakes. We find that water level
 declines occur when the imposed frequency is less than 2Hz, while the
 acceleration has weak correlation on the water level change when it is
 less than 0.5g. Sinusoidal wave propagation reduces hydraulic conductivity
 first sharply which then stabilizes at a constant value with a slight
 increase.  Heterogeneous consolidation, mechanical
 resonance, compaction, dilation, and re-packing of the grain
 structure may constitute a physically plausible mechanism for
 water level fluctuations and hydraulic parameters adjustment.
 Laboratory experiments can therefore provide quantitative and
 process-oriented approach to better understand water level
 response to seismic waves.
description: See attached readme.txt for additional information.