Theses and Dissertations

Issuing Body

Mississippi State University


Vahedifard, Farshid

Committee Member

Yarahmadian, Shantia

Committee Member

Peters, John F.

Date of Degree


Document Type

Graduate Thesis - Open Access


Civil Engineering

Degree Name

Master of Science


James Worth Bagley College of Engineering


Department of Civil and Environmental Engineering


The main goal of this research is to evaluate the behavior of earth pressure profiles in unsaturated soils under transient flow. In the first part, an empirical correlation is proposed to obtain the fitting parameters of Brooks and Corey’s soil-water retention model from Fredlund and Xing’s model. The retention models and the proposed equivalency between the models were assessed for 601 soil samples from the unsaturated soils hydraulic database (UNSODA). In the second part, a coupled one-dimensional hydro-mechanical model is introduced and is implemented into Rankine’s earth-pressure model to represent active and passive earth pressure profiles in unsaturated soils under transient flow. A realistic coupling process of infiltration and deformation in the porous medium is established based on the variation in permeability along with deformation in the soil body. The results showed that ignoring the hydro-mechanical coupling effect can lead to underestimation of earth pressure values, especially for fine-grained soils.