Civil Engineering Commons^™

Development Of Erosion Functions For Micp-Treated Beach Sand, Saeed Booshi

UNF Graduate Theses and Dissertations

This thesis investigates the effectiveness of microbially-induced calcium carbonate precipitation (MICP) using the recently introduced bioslurry treatment method via surface percolation. To simulate realistic water forcing conditions, a piston-style erosion rate testing apparatus, specifically the Florida Department of Transportation Sediment Erosion Rate Flume, was used. Initial tests conducted at a high shear stress of 42 Pa revealed that a combination of 15% bioslurry and 85% cementation solution exhibited the strongest erosion resistance when compared to other ratios between bioslurry and cementation solution. Subsequent experiments focused on separating the specimen into a "loose" part and a “surface crust,” with shear stresses …

Development Of Practical Assessment Techniques For Sinkhole Potential In Florida Based On Sinkhole Vulnerability Indices, Sylvia Pesha

UNF Graduate Theses and Dissertations

Sinkholes are natural geohazards prevalent in Florida's distinctive karst geology, posing risks to public safety, infrastructure, and groundwater integrity. Considering the increasing frequency of sinkhole occurrences in Florida due to land development in vulnerable soils, understanding the potential for sinkhole occurrence can aid in the identification of high-risk locations and inform effective mitigation strategies. Researchers have developed three point-based indices to be used when assessing the vulnerability a project site has to sinkhole formation based on the encountered subsurface conditions. Engineers have historically used an index based on the subsurface layer thicknesses, called the Raveling Index (RI). In recent years, …

Crystalline Analysis Of Geomicrobially-Induced Calcium Carbonate Precipitation In Sands Using A Surface Percolation Treatment Technique, Justin Edward Mulloney

UNF Graduate Theses and Dissertations

Ottawa 50/70 sand specimens and natural beach sand samples were treated using bio-augmented geomicrobies via a surface percolation technique. Testing was conducted on these specimens to determine how resultant calcium carbonate precipitation changed as a function of temperature, depth from the surface, and in the presence of magnesium. Specifically, x-ray Diffraction (XRD), a Scanning Electron Microscope (SEM), and Energy Dispersive X-ray Spectroscopy (EDS) were used to determine and quantify the presence of calcium carbonate and its associated phase. Results showed a direct relationship between temperature and precipitated calcium carbonate. In addition, as an unintended consequence associated with the treatment, ammonium …

Predicting Anthropogenic Underwater Pile Driving Noise Using Pile Driving Analyzer (Pda) Data, Brandon Alfredo Rivera

UNF Graduate Theses and Dissertations

In the past several years, there has been increasing concern about anthropogenic noise generated during marine pile driving. This concern is expected to increase concomitantly with increases in waterfront construction efforts associated with aging infrastructure and sea level rise. Several guidelines are available to help predict underwater noise transmission due to pile driving, but the issue with all these methods is that they require one to measure sound pressure levels at one locus or more from the driven pile. In the context of marine construction, adding specifications for underwater noise collection may be expensive or difficult because contractors typically have …

Soil Improvement Using Microbial Induced Calcite Precipitation And Surfactant Induced Soil Strengthening, Matthew P. Davies

UNF Graduate Theses and Dissertations

Microbially induced calcite precipitation (MICP) has been used for a number of years as a technique for the improvement of various geological materials. MICP has been used in a limited capacity in organic rich soils with varying degrees of success. Investigators hypothesized that microbially-induced cementation could be improved in organic soils by using a surfactant. Varying amounts of Sodium Dodecyl Sulfate (SDS) were added to soils of varying organic content and a mixing procedure was used to treat these soils via MICP. Treated specimens were tested for unconfined compressive strength (UCS). Results appeared to show direct relationships between SDS content …

Development Of Forward And Inversion Schemes For Cross-Borehole Ground Penetrating Radar, Donald Jones

UNF Graduate Theses and Dissertations

Tomography is an imaging technique to develop a representation of the internal features of material using a penetrating wave, such as an electromagnetic wave. The calculation method used is an example of an inverse problem, which is a system where the input and the output are known but the internal parameters are not. These parameters can be estimated by understanding the responses of a penetrating wave as it passes through the unknown media. A forward problem is just the opposite; the internal structure and input penetrating wave is known and the output is determined. For both forward and inverse problems, …

Potential Replacement Of The Us Navy's Rapid Penetration Test With The Method Of Multichannel Analysis Of Surface Waves, William Fletcher

UNF Graduate Theses and Dissertations

The United States Navy (USN) currently utilizes a Rapid Penetration Test (RPT) on both land and in water as the means to determine whether sufficient soil bearing capacity exists for piles in axial compression, prior to construction of the Elevated Causeway System (Modular) [ELCAS(M)] pile-supported pier system. The USN desires a replacement for the RPT because of issues with the method incorrectly classifying soils as well as the need to have a less labor-and-equipment-intensive method for geotechnical investigation.

The Multichannel Analysis of Surface Waves (MASW) method is selected herein as the potential replacement for the RPT. The MASW method is …

Strength Property Variability In Microbial Induced Calcite Precipitation Soils, Jacob Fuller

UNF Graduate Theses and Dissertations

Microbial Induced Calcite Precipitation (MICP) is an attractive alternative for a variety geotechnical ground improvement practices commonly used today and has a variety of potential applications. This research focuses primarily on its use as a soil stabilization technique using the bacteria Sporosarcina Pasteurii and a single injection point percolation method adapted from previous research in granular soils. This method, and most published data, show an inherent variability in both physical and engineering properties due to the distribution of precipitated calcite within the specimen. The focus of this research is on the quantification of the variability in shear strength parameters induced …