Theses and Dissertations

Date of Award

7-2021

Document Type

Thesis

Degree Name

Master of Science (MS)

Department

Civil Engineering

First Advisor

Dr. Chu-Lin Cheng

Second Advisor

Dr. Philip Park

Third Advisor

Dr. Jong-Min Kim

Abstract

Hydraulic properties of porous media are very important characters for various geotechnical and geo-environmental applications. In this study, multi-step outflow experiments and numerical modeling were performed for homogeneous and layered column conditions with fine to coarse sands to investigate water flow mechanisms and better predict water flow and solute transport with the van Genuchten-Mualem (VGM) hydraulic model. Inversed modeling under HYDRUS-1D was performed to estimate six VGM soil hydraulic parameters. Forward modeling was conducted to evaluate the impacts of VGM hydraulic parameters along with saturated hydraulic conductivity to solute transport. Scaling effects such as column length, time, and chemical parameters were also examined. The samples tested showed that hydraulic conductivity varied between 0.88-1.06 cm/min (fine sand) and 2.54-3.84 cm/min (coarse sand), which is greater than subsurface soil (0.03-0.9 cm/min) under field condition. In addition, the sensitivity analysis was also performed to investigate the influence of input parameters. The effects of VGM hydraulics parameters and measurement accuracy on concentration breakthrough curves were examined. The coefficient of variation (CV) results showed that the two most influential parameters were the hydraulic conductivity (53-93%) and saturated water content (46-53%).

Comments

Copyright 2021 Syed Istiyak Ahmed. All Rights Reserved.

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