Liquefaction tests using shaking table considering deposition angle of sand
Geotechnical Engineering Laboratory 
4th year Undergraduate Course@
Garcia Presas Jesus Everardo
Abstract
This study examines the influences of sand deposition angle on liquefaction resistance using a series of shaking table tests. Liquefaction indicates a phenomenon in which saturated loose sandy ground loses its strengths and behave like a liquid when the ground is suffered by strong seismic motions. Liquefaction can cause a severe structural damage, as observed during the 1964 Niigata Earthquake. To clearly understand this phenomenon, a shaking table tests, in which accelerometers and pore water pressure meters are embedded to estimate cyclic stress and excess pore water pressure ratio in a soil container, were conducted.
Liquefaction resistance was investigated in three different depositional angles, which are 0, 45, and 90 degrees. The sand deposited at 0-degree (horizontal orientation), showed the highest liquefaction resistance, indicating that the greatest number of cycles to liquefaction is needed. Conversely, the sand deposited at 90-degree (vertical orientation) was the most vulnerable to liquefaction, which means the smallest number of cycles is needed for liquefaction. Moreover, microscopy analysis was conducted to estimate the sand particle orientation before and after liquefaction. Regardless of initial depositional angle, soil particles tend to shift toward a more vertical alignment after liquefaction. The study concluded that the orientation of sand particles significantly affects liquefaction resistance, in which horizontally deposited sand presents more stable than vertical oriented sand under seismic loading. These findings contribute to a better understanding for ground reliquefaction behavior induced by earthquakes and could help in restoration works from liquefaction damage to make more resilient geotechnical structures.