Natural disasters such as earthquakes, El-Nino, tsunamis and water pollution have
a negative impact on human health and living environment. Some of these may give rise
to subsurface vibrations that can potentially increase groundwater pollution risks
in double-porosity systems. The more complicated situation was where underground storage
tanks and petroleum pipeline damage have caused the leakage of non-aqueous phase liquids
(NAPLs) which migrated into the groundwater resources. These problems need to be addressed
by both professionals and researchers worldwide to ensure the sustainability of groundwater
utilization. This paper aims to investigate and understand NAPL migration in vibrated
double-porosity soils. To do so it was necessary to study the phenomena and characteristic
of soil structure and the pattern of NAPL migration to identify cost-effective remediation
schemes. A laboratory experiment was conducted to study the phenomena and characteristics
of vibration response and NAPL migration in double-porosity soil deformation under
vibration effect using a digital image processing technique (DIPT). The outcomes of
the experiment show that the gradual increase of vibration table excitation frequency
yielded different vibration responses from the respective soils. This indicated that
soil surface acceleration depended significantly on the soil conditions, soil water
content, soil structure and the pattern of soil fracturing. NAPL migration was faster
in sample 2 with 150ml toluene than sample 1 with 70ml toluene and this could be because
the greater amount of toluene in sample 2 exerted an extra entry force on top of the
soil sample that had yet to migrate through the sample surface. Finally, it was concluded
that the DIPT may provide detailed information, and can be used to understand and
identify the remediation method as well as to ensure the sustainable consumption of
groundwater.
