摘要(英) |
Abstract
The study was conducted using the liquefaction tank on a
portable shaking table which was previously designed and
developed at Chaoyang University. The main purpose of the study
was to investigate the effects of soil grain shape on the
re-liquefaction related behavior of saturated sand deposits
including the energy required and resulting settlements compared
with those of the previous liquefaction. Three grain shapes were
used in the study including round, angular, and sheet grain
shapes.
The results of the study revealed that relative density Dr,
drainage condition within the liquefied soil mass and the time
elapsed between the previous liquefaction and the
re-liquefaction which may occur in after shocks following the
strong main shocks within a time interval ranging from minutes
to days are the controlling factors. The results of the study
revealed that greater relative density Dr, better drainage
condition and longer time period between the previous and the
re-liquefaction lead to higher re-liquefaction energy ratio N
and less settlement, among which the relative density Dr
exhibits the most significant influence. In addition, the sand
with sheet grain shape has the highest re-liquefaction energy
ratio N, which implies that more energy is required to liquefy
the soil mass with sheet grain shape compared with that for the
previous liquefaction, however, once the re-liquefaction occurs,
the settlements are the highest.
The results indicate that the re-liquefaction energy ratio N is
2.7 - 6 times and 1.1 – 2.3 times for sheet grain and angular
grain respectively compared with that of the round grain
shape. Also, the settlements resulted from re-liquefaction
compared with that from previous liquefaction is the least for
the angular grain which is about 0.43 – 0.63 time of that for
round grain. At the same time, the sheet grain exhibits
significantly greater settlements, once re-liquefied, which is
about 1.28 – 1.78 time of that for the round grain sand.
The study results provide useful information for earthquake
hazard mitigation for the areas where re-liquefaction due to
after shocks may occur. |