Department of Civil and Environmental Engineering

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The mission of the Department of Civil and Environmental Engineering at the University of Delaware is to provide a culturally diverse and intellectually stimulating environment for the discovery and application of knowledge in civil and environmental engineering, the education of our students to their fullest potential, and service to the public through outreach and professional activities.

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Browsing Department of Civil and Environmental Engineering by Subject "3D finite element analysis"

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    Column Supported Embankments with Geosynthetic Encased Columns: Parametric Study
    (Springer International Publishing AG, 2014) Khabbazian, Majid; Meehan, Christopher L.; Kaliakin, Victor N.; Khabbazian, Majid, Meehan, Christopher L., Kaliakin, Victor N.; Meehan, Christopher L. (orcid.org/0000-0002-9721-6275); Kaliakin, Victor N.
    Three-dimensional finite element analyses were performed to investigate different factors that affect the behavior of column supported embankments (CSEs) that are constructed using geosynthetic encased columns (GECs) as the deep foundation elements. Analyses were performed to study the influence of the geosynthetic encasement on the behavior of granular columns (GCs) in CSEs. Stress reduction ratios (SRRs) obtained from finite element analyses were compared to those calculated from ten different analytical solutions. Parametric analyses were also carried out to study the effect of variations in the stiffness of the encasement, the area replacement ratio, and the length of the geosynthetic encasement on the performance of CSEs. Finally, the sensitivity of the numerical results, particularly the lateral displacement of GECs, to the constitutive model that was used to simulate the behavior of the granular column material was examined. Numerical results showed that encasing a GC in a CSE not only improves the performance of the CSE but also enhances the behavior of the GC. No agreement was found between the calculated values of the SRR from finite element analyses and those from existing analytical solutions.
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    Column Supported Embankments with Geosynthetic Encased Columns: Validity of the Unit Cell Concept
    (Springer International Publishing AG, 2015) Khabbazian, Majid; Kaliakin, Victor N.; Meehan, Christopher L.; Meehan, Christopher L.; Kaliakin, Victor N.
    Column supported embankments (CSEs) are used to overcome common problems associated with the construction of embankments over soft compressible soils. The use of granular columns as deep foundation elements for CSEs can be problematic in soft soils due to the lack of adequate lateral confining pressure, particularly in the upper portion of the column. Using a high-strength geosynthetic for granular column confinement forms geosynthetic encased columns (GECs); the confinement imposed by the geosynthetic increases the strength of the column, and also prevents its lateral displacement into the soft surrounding soil. This paper presents the results of finite element analyses of a hypothetical geosynthetic reinforced column supported embankment (GRCSE) (i.e., a CSE underlain by geosynthetic reinforcement) that is constructed with GECs as the deep foundation elements. Full three-dimensional(3-d), 3-d unit cell, and axisymmetric unit cell analyses of the GRCSE were carried out to investigate the validity of the unit cell concept. The effect of the degree of nodal constraint along the bottom boundary when numerically modeling GRCSEs was also studied in this paper. Numerical results show that a full 3-d idealization is required to more precisely determine the tension forces that are produced in the geosynthetic reinforcement that underlies the GRCSE. A number of design parameters such as the average vertical stresses carried by the GECs, lateral displacement of the GECs, and the maximum settlement of the soft foundation soil, however, can be successfully calculated using unit cell analyses.