Geotechnical Engineering Commons^™

Performance Of Geotechnical Systems Under Extreme Hydroclimatic Events Using Finite Element Modeling, Tharshikka Vickneswaran

All Dissertations

Failure of geotechnical systems during hydroclimatic events such as heavy rainfall, flood, and drought often leads to significant socio-economic loss. The time-dependent stability and deformation behaviors of geotechnical systems subjected to hydroclimatic events must be investigated using a coupled flow-deformation formulation because the strength and deformation parameters vary with the degree of saturation and/or matric suction of the soil. Although the impacts of the hydroclimatic events on the geotechnical systems are assessed and summarized in the previous studies, all the analyses were carried out in a loosely coupled manner and/or uncoupled manner without considering the effects of water flow in …

Experimental And Numerical Analysis Of Soil-Geosynthetic Composite For A Geosynthetic-Reinforced Roadway System, Daniel Robertson

Department of Civil and Environmental Engineering: Dissertations, Theses, and Student Research

The present research conducted tests to evaluate the reinforcing performance of geosynthetics including three geogrids (GG1, GG2, and GG3) and one geotextile (GT) for three different soil types – sand, clay, and red shale. All geosynthetics showed great improvement under the lowest confining pressure. The report concluded that between the Large-Scale Direct Shear test, the Large-Scale Pullout Box, and the FLAC simulation, the three geogrids showed the greatest improvement when conducted with sand. The sand could withstand a much greater normal pressure than either clay or red shale. The biaxial geogrids, GG1 and GG3, had ideal results for lower stress …

Investigation Of Groundwater Depletion And Leveel Underseepage With Unstructured-Grid Modeling Approach, Ye-Hong Chen

LSU Doctoral Dissertations

Unstructured grid is a tessellation of geometric shapes in irregular patterns that provides flexibility in grid design for groundwater modeling. However, groundwater modeling is mostly developed with uniform grid tessellation and layer, which could simplify model structure or cause expensive computational costs in high-resolution simulations. Unstructured grid incorporates non-uniform horizontal and non-uniform vertical discretizations providing the capability to replicate complex hydrostratigraphy, capture geologic features that are crucial for groundwater flow simulation, and reduce computational costs while maintaining a high resolution for areas of interest. This study contains three parts to investigate unstructured-grid approach on constructing high-fidelity groundwater models, comparisons with …

A Coupled Smoothed Particle Hydrodynamics-Discrete Element Method Framework For The Dynamic Response Of Saturated Geotechnical Systems, Saman Farzi Sizkow

Civil and Environmental Engineering Theses and Dissertations

Investigating the past failures of various geotechnical systems during major seismic events, reveals the importance of developing a robust framework that can reliably analyze complex geotechnical systems. Up to now, fully continuum techniques have been the most popular choice for this type of problems. These methods use sophisticated constitutive models which need careful fine-tuning to successfully mimic the macro-scale dynamic behavior of coupled systems. The discrete element method (DEM) is, by nature, the best option for discontinuous systems such as soil. Furthermore, it has effective means to handle soil-structure interaction. Therefore, many attempts have been made to couple DEM with …

Resilient Modulus Of Siliciclastic Unbound Granular Materials Under Repeated Wheel Loading, Siya Rimoyi

Tanzania Journal of Engineering and Technology (TJET)

The Resilient Modulus (Mr) is a fundamental material property input in modern Mechanistic-Empirical (M-E) pavements structural design. Empirical pavement design methods have been in use over a long period during which large databases of four- days-soaked California Bearing Ratio (CBR) values at or near the Maximum Dry Density have been generated in the strength assessments for Unbound Granular Materials (UGMs). In the adoption of the M-E design approach researchers have so far attempted with various degrees of success to develop models to derive resilient modulus from the conventional CBR-based databases. This study provides an extensive laboratory experimental study to investigate …

Development Of Intensity-Duration-Frequency (Idf) Models For Manually Operated Rain Gauge Catchment: A Case Study Of Port Harcourt Metropolis Using 50 Years Rainfall Data, Francis Ogbozige

Tanzania Journal of Engineering and Technology (TJET)

Hydraulic structures such as surface drainages and culverts are usually constructed in urban areas with the intention of draining runoff into nearby streams and rivers in order to avoid flooding. However, most of these structures frequently fail to serve the intended use due to the occurrence of high intensity rainfall accompanied with long duration, which produce runoff discharge higher than their designed capacities. This is common in many developing countries as drainages and culverts are most times constructed without considering hydrological analysis of the catchment. Hence, this research considered Port Harcourt city as a case study by utilizing 50 years …

Essai Sur Le Terrain Du Mini Pipe Strain Meter Du Jniosh Comme Système D’Alerte De Sécurité Lors Des Travaux En Tranchée, André Lan, Bertrand Galy, Satoshi Tamate, Tomohito Hori, Nabutaka Hiraoka

Rapports de recherche scientifique

Les travaux en tranchée exposent les travailleurs à de nombreux risques. Le risque d'effondrement est le plus important et le plus fréquent lors de tels travaux, mais il est malheureusement très souvent sous-estimé, car même un effondrement mineur ou partiel de moins de 1 m3 de sol peut mortellement blesser un travailleur. L'analyse de 59 rapports de la Commission des normes, de l'équité, de la santé et de la sécurité du travail (CNESST) concernant des accidents graves et mortels survenus lors de travaux d'excavation et en tranchée réalisés entre juin 1973 et mai 2015 montre qu'il y a eu 51 …

Field Test Of The Jniosh Mini Pipe Strain Meter As A Safety Alert System During Trench Work, André Lan, Bertrand Galy, Satoshi Tamate, Tomohito Hori, Nabutaka Hiraoka

Rapports de recherche scientifique

Les travaux en tranchée exposent les travailleurs à de nombreux risques. Le risque d'effondrement est le plus important et le plus fréquent lors de tels travaux, mais il est malheureusement très souvent sous-estimé, car même un effondrement mineur ou partiel de moins de 1 m3 de sol peut mortellement blesser un travailleur. L'analyse de 59 rapports de la Commission des normes, de l'équité, de la santé et de la sécurité du travail (CNESST) concernant des accidents graves et mortels survenus lors de travaux d'excavation et en tranchée réalisés entre juin 1973 et mai 2015 montre qu'il y a eu 51 …

Characterization Of Shear Strength And Cracking Resistance Of A Chemically Stabilized Clayey Soil, Abdulaziz Alhawiti

Electronic Theses and Dissertations

Improving the engineering properties of the subgrade soil by means of chemical stabilization is known to enhance the construction conditions in plastic soils and result in a reduction in design thickness requirements of the base, subbase, and wearing course in a layered pavement structure. This can also potentially lead to an increase in pavement life. This study was undertaken to study the effect of hydrated lime and Portland cement used as a stabilizing agents on the strength properties and the cracking resistance of a clayey soil collected from South Dakota. Hydrated lime was mixed with the collected soil by 2%, …

Image-Data-Driven Deep Learning For Slope Stability Analysis, Behnam Azmoon

Dissertations, Master's Theses and Master's Reports

Landslides cause major infrastructural issues, damage the environment, and cause socio-economic disruptions. Therefore, various slope stability analysis methods have been developed to evaluate the stability of slopes and the probability of their failure. This dissertation attempts to take advantage of the recent advancements in remote sensing and computer technology to implement a deep-learning-based landslide prediction method.

Considering the novelty of this approach, this dissertation leads with proof-of-concept studies to evaluate and establish the suitability of deep learning models for slope stability analysis. To achieve this, a simulated 2D dataset of slope images was created with different geometries and soil properties. …

Analysis Of Shear Failure In Ultra-High Performance Concrete Beams, Kevin Conway

Electronic Theses and Dissertations, 2020-2023

Ultra-high performance concrete (UHPC) is an emerging cementitious material type currently undergoing research in different structural applications. This material is characterized by a compressive strength of 150 MPa (22 ksi), according to the Association Francaise de Genie Civil and the Federal Highway Administration, high tension strength, and high durability. Additionally, UHPC consists of secondary reinforcement in the form of steel or polymeric fibers, which enable UHPC to exhibit tension hardening behavior and tension ductility previously ignored in conventional concrete mixes. Previous research has focused on applications in the transportation and bridge design industries; however, applications in buildings and other heavy …

Development Of A Decision-Making Tool For Prediction Of Rainfall-Induced Landslides, Faisal Shakib Ahmed

Theses and Dissertations--Civil Engineering

Landslides are frequently observed in mountainous places following prolonged periods of rain, frequently resulting in substantial topography changes. They pose a significant risk to human lives and the built environment globally, particularly in areas prone to excessive rainfall. While slope failures can occur because of human-caused factors such as slope loading or toe cutting for construction purposes, many failures occur because of rainfall penetrating an otherwise stable slope. A greater understanding of the characteristics and mechanics of landslides is consequently critical for geotechnical research, particularly in evaluating prospective mitigation strategies. The potential of slope failure is a primary consideration when …

Load And Pressure Distribution As A Function Of Dynamic Contact Stress At The Railroad Crosstie-Ballast Interface, Habib Abdil Unluoglu

Theses and Dissertations--Civil Engineering

Excessive crosstie wear and abrasion and ballast wear and fouling are two of the fundamental problems contributing to inadequate railroad track performance. This adversely affects the attainment and long-term maintenance of desired track geometric requirements. The magnitudes and distribution of the stresses at the crosstie-ballast (CT-B) interface must be known to determine the stress distribution on the ballast. However, the stresses at the top of the ballast often vary significantly. This study examines a new approach to predicting dynamic contact pressures at the interface of crosstie and ballast using the ‘square wave theory.’ A data set of in-track CT-B interfacial …

Geophysics-Based Ground Control And Excavation Design Methodology Based On Acceptable Damage, Jorge Romana Giraldo

Theses and Dissertations--Civil Engineering

This dissertation is structured around a novel conceptual framework for designing deep excavation retaining systems and using geophysical data to estimate the mechanical response of soft soil deposits. It begins with presenting an approach to design excavation retaining walls based on limiting damage to adjacent infrastructure. In this approach, the damage is defined based on critical distortions of an idealized laminate beam model used for representing the adjacent building deformations. The wall and support elements of the support system are then designed such that the system yields the limiting ground deformations. The resulting excavation support system limits damage to adjacent …

Methodology For Enhanced Filtration And Dewatering Of Fine-Grain Amd Precipitate Using Geocomposites For Rare Earth Elements Recovery, Iuri Lira Santos

Graduate Theses, Dissertations, and Problem Reports (ETD)

Research performed by the West Virginia Water Research Institute (WVWRI) in partnership with the Department of Energy (DOE) has identified that coal mining by-products contain significant amounts of Rare Earth Elements (REEs). REEs currently are in high demand, and extraction from coal mining reject presents a potential for commercialization if extraction is feasible. The coal mining reject include Acid Mine Drainage (AMD) in the aqueous phase and sludge from AMD treatment. A novel two split selective precipitation method was implemented to remove gangue metals, increasing the concentration of REEs in the sludge.

This process presents a two-fold benefit: 1) treatment …

Non-Destructive Characterization Of Bio-Cemented Soils Via Seismic Wave Measurement, Kyle Best

Williams Honors College, Honors Research Projects

The final outcome of this project is to examine the mechanical and resulting physical properties of bio-treated soil through microbial activity via non-destructive testing by seismic waves. The proposed bio-treatment strategy is through supplying specific nutrients for indigenous microbes within a soil specimen which in return produce calcium carbonates. The bio-minerals produced during these biogeochemical activities will improve the mechanical properties of soil by making cementation between soil grains. Additionally, a theoretical laboratory experimentational description will be provided to explain any associative effects on a specimen's water permeability or mechanical strength due to bio-mineralization within the samples. The characterization of …

Spatiotemporal Analysis Of Taxi And Transportation Network Companies (Tnc) Demand In The Wake Of Covid-19, Dewan Ashraful Parvez

Electronic Theses and Dissertations, 2020-2023

The objective of the thesis is to understand the factors affecting spatiotemporal ridehailing demand patterns as the COVID-19 pandemic has evolved. Specifically, the current study examines the key contributing factors of weekly ridehailing demand by employing Taxi and Transportation Network Companies (TNC) trip data from January 2019 through December 2020 for New York City. The ridehailing demand is partitioned across four time periods including Morning Peak, Morning Off Peak, Evening Peak and Evening Off Peak to accommodate for the time-of-day specific variations. Drawing on the high-resolution NYC data, the current study developed pooled spatial panel models to accommodate for the …

North 14th Street Corridor Improvements Project, Ashley Nguyen, Samantha Corey, Maricela Paramo Reyes, Pooja Rajeev

Honors Program: Senior Projects (Public)

The following project report was a study of the North 14^th Street corridor ranging from Adams Street to Virginia Street conducted by University of Nebraska-Lincoln students for a senior design capstone project. Main focuses of the project were the intersection of Adams and 14^th Street and the 14^th Street bridges over Cornhusker Highway and Oak Creek. Study of this area included work in transportation, traffic, structural, geotechnical, water resources, and environmental engineering. However, this report done by students should not take the place of work done by licensed professional engineers.

This project was done in collaboration with …

Comparative Analysis Of Bridge Abutment Types, David Fell

Williams Honors College, Honors Research Projects

This project was developed to serve as a brief overview of design practices and considerations in the selection of highway bridge abutment types. This involved a review of literature in the form of reviewing national design guides and department of transportation (DOT) requirements from both US DOTs and international DOTs. The abutment types covered in this research included conventional reinforced concrete abutments with bearings, integral abutments, and semi-integral abutments. This research focused solely on highway bridge abutments, particularly on Ohio Department of Transportation design requirements due to their extensive use of semi-integral abutments. Superstructure elements and geometric requirements are primary …

Investigation Of Casting Methods Of Photoelastic Particles To Study The Geomechanics Of Granular Media, Daniel Schullek

Williams Honors College, Honors Research Projects

The research being conducted within this project is to observe force chains in different samples of soil media with varying shapes. The method for observing the force chains is a process called photoelasticity. Photoelasticity uses two polarizing sheets, with the clear media being tested placed between, and light is directed through the sheets to observe how the light is refracted as force is applied to the tested media. Through our research, we are coming up with a method of casting soil particles through the utilization of resin, silicone, and 3D printing. Once the clear particles have been cast, we will …