Doctoral Dissertations

Keywords and Phrases

Chemomechanical behavior; Elastoplastic modeling; Hydromechanical behavior; Hysteresis behavior; Undrained loading; Unsaturated soils


"Unsaturated soils are often used as a construction material in transportation infrastructures; in which it is subjected to cyclic traffic loadings and/or seasonal wetting-drying cycles. While mechanical hysteresis is a common feature of soils in general, hydraulic hysteresis is associated with unsaturated soils. Most existing constitutive models paid limited attention to the mechanical and hydraulic hysteresis behavior of unsaturated soils. This research presents a three-dimensional model for unsaturated soils and a chemo mechanical model for saturated soils. The unsaturated soils’ model has the following characteristic features: (a) the hydraulic and mechanical behaviors are fully coupled under 3D conditions; (b) it provides consistent predictions for different soil phases; (c) it has a smooth transition between saturated and unsaturated soil states; (d) it considers both the mechanical and hydraulic hysteresis; (e) it accounts for the high non-linearity of the hydraulic behavior; (f) it uses only one yield curve to represent the yielding of both mechanical and hydraulic behaviors. Moreover, in this research, conventional oedometer and direct shear tests apparatus were modified to fully characterize the behavior of unsaturated soils under cyclic undrained loading conditions. Therefore, an experimental testing program was designed and performed to validate the model proposed for unsaturated soils. In addition to the unsaturated soils model, chemo mechanical model was developed to simulate the behavior of contaminated saturated soils. It accounts for the non-linear shear strength behavior, and the change in yield stress, soil stiffness, and plastic deformations due to chemical presence"--Abstract, p. iv


Zhang, Xiong

Committee Member(s)

Yan, Guirong "Grace"
Olgun, Guney
Liu, Jenny
He, Xiaoming


Civil, Architectural and Environmental Engineering

Degree Name

Ph. D. in Civil Engineering


Missouri University of Science and Technology

Publication Date

Spring 2022


xvii, 259 pages

Note about bibliography

Includes_bibliographical_references_(pages 252-258)


© 2022 Beshoy Sami Moussa Riad, All Rights Reserved

Document Type

Dissertation - Open Access

File Type




Thesis Number

T 12232