Topic: Migration of Aqueous and Non-Aqueous Phase Liquids in Deformable Double-Porosity Soil under Earthquake Effects
Speaker: Dr. Hj Ramli Nazir / Assoc. Professor Universiti Teknologi, Malaysia
Abstract: A rapid growth and development of the country has contributed to the underground storage tank leakage and surface spillage of hydrocarbon liquid and industrial chemicals into the double-porosity subsurface. This lead to groundwater contamination of aqueous phase liquids (APL) and non-aqueous phase liquids (NAPL) which cause a harmful effect on the environment and health issues. A comprehensive understanding of contaminate migration is important to ensure the sustainability of geo-environmental and groundwater utilization. This keynote address is intended to make understand the phenomena and characteristic of APL and NAPL migrations in double-porosity soil under earthquake effect and intact condition. A laboratory model was simulated to show the effect of vibration imposed to the double-porosity and vibration response using vibration table and accelerometer. The APL and NAPL migrate simulation results were obtained using digital image processing techniques. The recorded images were analyzed using Matlab special self-development routine and Surfer software to plot the hue saturation intensity (HSI) of the APL and NAPL migration characteristic. The same method was performed to develop a NAPL saturation calibration curve for verifying the hue values of the image to the actual NAPL saturation in fractured double-porosity soil. The multiphase flow and pollutant transport model for NAPL migration developed by Galerkin’s weighted-residual method was applied with the temporal discretization via implicit scheme. The simulated results using saturation calibration curve data compared to the works of previous researchers for validation purposes. The outcome shows that the deformable double-porosity soil has more fractured pores compare to the intact double-porosity soil. From the acceleration response analysis, it was seen that the soil samples has amplification and dis-amplification shaking. Thus, the fractured double-porosity soil has high permeability due to faster APL and NAPL migration and not uniformly downward due to the non-homogeneity of the fractured double-porosity under vibration process compared to intact double-porosity soil. The multiphase immiscible flow and pollutant transport model produce a faster penetration of NAPL in fractured double-porosity soil compared to intact double-porosity and single-porosity soil. In conclusion, it has shown that the multiphase flow model and HSI contour plot of APL and NAPL migration characteristic can provide detailed information of liquid migration. This can expedite researchers to comprehensively understand and simulate the liquids migration pattern that influence the groundwater resources. It is useful for future environmental sustainability of natural resources especially in susceptible earthquake zone area.