Ghasemi-Fare awarded grant for understanding the interaction of temperature, pore water pressure and pore fluid flow

September 26, 2018

Headshot of Omid Ghasemi-Fare

Dr. Omid Ghasemi-Fare, a professor in the Department of Civil and Environmental Engineering, was awarded a grant for his research to study the effect of temperature on soil behavior. Specifically, his research focuses on how interactions of temperature, Pore water pressure in soil media.

“This is a fundamental research, so that the next step can be to design waste disposal, etc.,” said Ghasemi-Fare. “This will help us to find out how the temperature changes the soil behavior. The daily temperature changes needs to be considered.”

His current efforts are a continuation of his research in geomechanics, geothermal energy and energy geo-structures. Through his study on potentially utilizing that geothermal energy as a localized fuel source, he became interested in how those changes in the soil medium impact the soil permeability and soil behavior.

The study looks the thermally induced pore fluid flow in coarse and fine soil, and how fluctuations in temperature effect both. For coarse soil, as the soil temperature increases the heat convection through pore water flow begins. Fine soil however, is more difficult for water to flow through, as temperature changes increase pressure in the ground. Beside dissipation of thermally induced pore water pressure makes soil displacement and can lead to thermal consolidation.

“As the temperature rises and we get the thermal consolidation, for the deep soil, we could use the thermally enhanced ground, and soil will be better for load bearing. Thermal consolidation makes the soil stiffer,” said Ghasemi-Fare. “For reducing the settlement of infrastructure on clay soil we have to do ground modification. In the design phase, we always have to check for consolidation. Preloading is the first option we study in the design phase. However preheating the soil, can also make the pre consolidation.”

As different soil mediums react differently to the fundamentals of temperature, his focus is on quantifying those disparities to more effectively calculate the permeability variation with temperature and integrity of the ground. Ideally, the results of his experimental models can be applied not only to streamlining processes for strengthening a structural base, but have applications that will help with waste disposal design, as well as the permeability changes of landfills due to chemical reactions.

Additionally, he hopes that the outcomes of the current study will be useful for multi-physics, a field of research that consider computational simulations to model flow in porous media and similar complex problems.

“During the literature review phase we found inconsistencies in research. There is no certainty in how temperature impacted soil permeability, and changes in permeability has not been considered in thermal consolidation,” said Ghasemi-Fare. “In terms of the practice, they don’t do a thermal consolidation, they do pre-loading. We’ve done it for years, but this is a new tool. The problem with pre-loading for deep soil is that it is not as efficient as shallow depth.”

The grant from the National Science Foundation started on August 1, 2018, running three years until July 31, 2021.