PhD, University of Cincinnati, 2010, Arts and Sciences : Geography

Unchecked human development has ravaged the region between Dominical and Uvita, Costa Rica. Much of the development transition has been driven by tourism and further foreign direct investment in residential, service and commercial enterprises. The resulting land-use/land-cover change has removed traditional forest cover in exchange for impervious surfaces, physical structures, and bare ground which is no longer mechanically supported by woody vegetation. Combined with a tropical climate, deeply weathered soils and lithography which are prone to erosion, land cover change has led to an increase in slope failure occurrences. Given the remoteness of the Dominical-Uvita region, its rate of growth and the lack of monitoring, new techniques for monitoring land use and slope failure susceptibility are needed. Two new indices are presented here that employ a Digital Elevation Model (DEM) and widely available Landsat imagery to assist in this endeavor. The first index, or Vegetation Influenced Landslide Index (VILI), incorporates slope derived from a DEM and Lu et al.'s (2007) Surface Cover Index to quantify vegetative cover as a means of mechanical stabilization in landslide prone areas. The second index, or Slope Multiplier Index (SMI), uses individual Landsat data bands and basic Landsat band ratios as environmental proxies to replicate soil, vegetative and hydrologic properties. Both models achieve accuracy over 70% and rival results from more complicated published literature. The accuracy of the indices was assessed with the creation of a landslide inventory developed from field observations occurring in December 2007 and November 2008. The creation of these indices represents an efficient and accurate way of determining landslide susceptibility zonation in data poor areas where environmental protection practitioners may be overextended, under-trained or both.

Committee: Nicholas Dunning PhD (Committee Chair); Kenneth Hinkel PhD (Committee Member); Robert Frohn PhD (Committee Member); Mark Bowers PhD (Committee Member) Subjects: Geography

Master of Science, The Ohio State University, 2021, Earth Sciences

The Chandeleur Slide is a large submarine landslide on the Gulf of Mexico seafloor in approximately 1100 meters of water, 200 km southeast of New Orleans, LA. This part of the Mississippi Fan received high sedimentation throughout the Pleistocene, causing high pore fluid pressure and abundant slope failures, though few as large as the Chandeleur. Given its proximity to major coastal cities, oil and gas infrastructure, and its large size, I examine the Chandeleur Slide to: (1) map the location and thickness of the displaced sediment, (2) understand what led to the initial slope failure, (3) decipher if this was a fast-moving or slow-moving event, and (4) consider potential hazard implications a slide like the Chandeleur represents for seafloor infrastructures and tsunami risks to coastal communities surrounding the Gulf of Mexico. I interpreted publicly available 2D and 3D multichannel seismic surveys and high-resolution bathymetry data to reveal several flow paths generally due south/southeast, and a slow-moving sediment mass with a translational-rotational behavior. The Chandeleur Slide includes extensional faulting in the headscarp area and compressional structures in the northern-most toe confined by a natural ramp-like structure. Beneath the Chandeleur Slide, I observe an upward-migrating salt body that has compressed a regional sand-rich unit (the Blue Unit). I interpret that the upward-migrating salt led to overpressure within Blue Unit sand layers, facilitating the initial failure of the Chandeleur. After failure, the Chandeleur Slide transported a large volume of sediment southward but was blocked by antecedent topographic highs that deflected much of the sediment to the south/southwest. The initial failure was followed by retrogressive headwall retreat northward, which created the prominent scarp on the seafloor. In total, the Chandeleur Slide comprises an area just over 1000 km2 and contains about 300 km3 of failed sediment.

Committee: Derek Sawyer Dr. (Advisor); Ann Cook Dr. (Committee Member); Daniel Pradel Dr. (Committee Member) Subjects: Earth; Environmental Geology; Geographic Information Science; Geological; Geology; Geomorphology; Geophysics; Geotechnology; Marine Geology

Doctor of Philosophy, The Ohio State University, 2021, Earth Sciences

Tsunami waves pose deadly threats to coastal communities worldwide. While earthquakes are a primary trigger for tsunami, submarine landslides are capable of generating tsunami by themselves or amplifying an earthquake-triggered tsunami. Velocity and mass are critical factors that dictate the size (and therefore severity) of a slide-generated tsunami. While mass is relatively easy to constrain, velocity remains highly uncertain and can vary over several orders of magnitude from creep-like rates to tens of meters per second. Seismic reflection data are well-suited to image the geometry and internal facies of submarine landslide deposits, however, the major goal of my dissertation is to link the deposit characteristics as observed in seismic data to infer slide velocity. Here I focus on the Cascadia margin offshore Oregon because of the range of landslide behaviors and a suite of newly acquired seismic reflection data that I participated in collecting in 2017. A well-defined head scarp and blocks from the largest blocky slide offshore Oregon, 44-North slide, are both captured in one of the 2017 seismic profiles, as well as a beautiful compressional deformation zone immediately seaward of the large landslide blocks. My analysis suggests that the 44-North slide was fast-moving with speeds of up to 38 m/s and impacted the seafloor with sufficient force to initiate deformation across this observed zone of deformation. I then studied the entire margin to understand how unique this 44-North Slide is and also explored what controls the morphological differences in landslides along the broader Oregon margin. The northern Oregon margin is characterized by more frequent slope failures with smaller disintegrative deposits (8 - 70 m) being more common. The southern Oregon margin is characterized with less slope failures, however they are much larger (21 - 410 m) and blockier than those found in the north. These differences may be explained by the relationship between sedi (open full item for complete abstract)

Committee: Derek Sawyer (Advisor); Ann Cook (Committee Member); W. Ashley Griffith (Committee Member); Matthew Saltzman (Committee Member) Subjects: Geology; Geophysics; Marine Geology

MS, Kent State University, 2018, College of Arts and Sciences / Department of Earth Sciences

This study uses previously obtained marine geophysical data for the proposed Galsi pipeline route from Algeria to Sardinia to analyze the buried salt distribution and calculate the amounts of fault displacements associated with halokinesis. Crossing the convergent African/Nubian–European plate boundary, the southern section of the proposed pipeline route traverses' continental shelves and slopes of Algeria and Sardinia, as well as the Algerian abyssal plain of the Western Mediterranean. Deeply buried Messinian-age salt is present throughout this area. With its low compressibility, salt is less dense and, therefore, more buoyant than the clastic overburden sediment, and thus tends to flow and form diapiric structures. Salt diapirs rise and push on overlying sediments, steepening slopes and causing faults to form. Fault displacements above diapiric structures were compared near the compressive plate boundary with those within passive margin environments. Measured offsets from seismic profiles of different resolutions are associated in this study with predicted sediment age at depth of each offset. The offsets were then used to calculate an average rate of movement along faults of 1.5 cm/ky. The highest rates along faults associated with halokinesis are along the Cagliari slope near Sardinia (2.5 to 2.7 cm/ky) and near the convergent plate boundary (2.3 cm/ky). In addition to faulting, one of the major threats to underwater pipelines can be submarine landslides. Due to decreased frictional resistance to sliding because of pore pressure, submarine landslides can occur at very low slope angles and can spread for much greater distances than terrestrial slope failures. Utilizing the same marine geophysical surveys and geotechnical data, analysis of the frequency and aerial extent of underwater failure events in this area can be linked, partially, to the distribution and nature of Messinian-age evaporites and the influence of salt tectonics (halokinesis). Turb (open full item for complete abstract)

Committee: Abdul Shakoor Dr. (Advisor); Daniel Holm Dr. (Committee Member); Christopher Rowan Dr. (Committee Member); William Johnson (Committee Member) Subjects: Geology

PHD, Kent State University, 2018, College of Arts and Sciences / Department of Earth Sciences

The Drift Creek watershed is a source of drinking water for the Confederated Tribes of Siletz Indians (CTSI) and Lincoln City and is a reproductive habitat for endangered salmon and trout species. The watershed has been designated as “Impaired by Unknown Stressors” by the MidCoast Watersheds Council Biological Monitoring Results Survey (2013). The Oregon Department of Geology and Mineral Industries (DOGAMI), the Oregon Department of Environmental Quality (DEQ), and the CTSI suspect that landslides may be causing water quality deterioration. This study maps landslide distribution and landslide susceptibility; determines physical properties of landslide-prone soil and rock; and estimates soil loss resulting from landslide-derived sediment within 30 m of Strahler 3rd order or higher streams in the Drift Creek watershed. Five hundred and seventy landslides were mapped using light detection and ranging (lidar) imaging, orthophotographs, and field observations. Debris flow and fluvial incision are controlling the relief in the Siletz River Volcanics; while deep seated landslides (landslides through bedrock) are controlling the relief in the Tyee Formation. Logistic regression was used to determine the most significant variables contributing to the probability of landslide occurrence and to create a watershed scale landslide susceptibility map. The susceptibility model can be focused to determine the probability of landslide occurrence for any specific area of interest (near a stream, a road, human related activity such as residential and commercial construction and trails, etc.) in the watershed. Rock durability ranges from very low to medium high. Siletz River Volcanics and Tyee Formation soils in the Drift Creek watershed fail in a brittle manner when sheared at natural water content, have a narrow range of plasticity, and have residual friction angles near the pre-failure slope angles for their respective landslide deposits. The soil loss model developed for this study (open full item for complete abstract)

Committee: Abdul Shakoor PHD (Advisor); Daniel Holm PHD (Committee Member); Neil Wells PHD (Committee Member); Mandy Munro-Stasiuk PHD (Committee Member); Christopher Blackwood PHD (Committee Chair) Subjects: Environmental Geology; Environmental Science; Geographic Information Science; Geology; Materials Science

Master of Science, The Ohio State University, 2015, Earth Sciences

Recently acquired 2-D seismic data from offshore North Carolina provides images of salt diapirs and landslides in the region of the Carolina Trough that give insight into the interaction between slope sediments and intruding salt from below. The best example of this is the Cape Fear Slide Complex in which the lower headwall of the slide surrounds at least two salt diapirs. Here, we present seismic images that were collected for the Eastern North American Margin Community Seismic Experiment, which we use to gain new insights into the sedimentary features present in this area, including new evidence for the location of the top of salt of the Cape Fear diapir (approximately 665 meters below seafloor). In addition, we analyze the morphology of the slide and Cape Fear diapir, and use an analytical model to infer a rate of vertical salt rise both before and after the occurrence of the Cape Fear landslide. Using this method we have estimated post-failure growth rates of 357 meters per million years (m/Ma), and pre-failure growth rates of 319 m/Ma. Furthermore, based on the post-failure salt growth rate we estimate that the salt has only risen between 4 and 10 meters since the landslide happened, assuming the published age range for the landslide. With this in mind, further analysis of the slope geometries on the flanks of the Cape Fear diapir mound prompt us to suggest that it is highly unlikely for the rise of salt itself to have triggered the Cape Fear landslide through oversteepening. Instead we believe there to be a more complex story, in which the salt may have primed this area of slope for failure while another mechanism, such as dissociating gas hydrates or an earthquake may have acted as the eventual trigger of the Cape Fear event.

Committee: Derek Sawyer (Advisor); Ian Howat (Committee Member); Joachim Moortgat (Committee Member) Subjects: Earth; Geological; Geology; Geophysical; Geophysics

Doctor of Philosophy, The Ohio State University, 2015, Civil Engineering

Landslides are natural disasters that cause environmental and infrastructure damage worldwide. In order to reduce future risk posed by them, effective detection and monitoring methods are needed. Landslide susceptibility and hazard mapping is a method for identifying areas suspect to landslide activity. This task is typically performed in a manual, semi-automatic or automatic form, or a combination of these, and can be accomplished using different sensors and techniques. As landslide hazards continue to impact our environment and impede the lives of many, it is imperative to improve the tools and methods of effective and reliable detecting of such events. Recent developments in remote sensing have significantly improved topographic mapping capabilities, resulting in higher spatial resolution and more accurate surface representations. Dense 3D point clouds can be directly obtained by airborne Light Detection and Ranging (LiDAR) or created photogrammetrically, allowing for better exploitation of surface morphology. The potential of extracting spatial features typical to landslides, especially small scale failures, provides a unique opportunity to advance landslide detection, modeling, and prediction process. This dissertation topic selection was motivated by three primary reasons. First, 3D data structures, including data representation, surface morphology, feature extraction, spatial indexing, and classification, in particular, shape-based grouping, based on LiDAR data offer a unique opportunity for many 3D modeling applications. Second, massive 3D data, such as point clouds or surfaces obtained by the state-of-the-art remote sensing technologies, have not been fully exploited for landslide detection and monitoring. Third, unprecedented advances in LiDAR technology and availability to the broader mapping community should be explored at the appropriate level to assess the current and future advantages and limitations of LiDAR-based detection and modeling of land (open full item for complete abstract)

Committee: Dorota Grejner-Brzezinska (Advisor); Charles Toth (Advisor); Tien Wu (Committee Member) Subjects: Civil Engineering

Doctor of Philosophy, University of Akron, 2014, Civil Engineering

Landslides and slope failures occur frequently every year to have major impact on the operational safety of roadways and to add financial burden to the highway agencies for slope repairs and maintenance. In this dissertation, a reliability-based computational algorithm is developed for design of a row of equally spaced drilled shafts and/or anchors to stabilize an unstable slope while achieving the required target reliability index with minimum volume of drilled shafts. The Monte Carlo simulation (MCS) technique is used in the previously developed deterministic computational program, in which the limiting equilibrium method of slices is modified to incorporate the arching effects of the drilled shafts in a slope. Uncertainties of soil parameters in the slope are considered by statistical descriptors, including mean, c.o.v., and distribution function. Model errors of the semi-empirical predictive equation for the load transfer factor for characterizing the soil arching effects are considered by statistics of bias. A PC-based program has been developed based on the above methodology. In order to dealing with small probability events in the drilled shaft/slope system and reduce the large number of MCS calculations, a more advanced methodology, importance sampling technique (IST), is proposed to determine the probability of failure and the reliability index of a drilled shaft/slope system. The performance function and the design point are determined by the ordinary method of slices (OMS) with the accompanying load transfer factor. To permit system reliability analysis for an anchor/slope system considering the effects of stochastic corrosion, the Monte Carlo simulation technique is used in conjunction with the modified limiting equilibrium method of slices. Meanwhile, the time-dependent deterioration of bond capacity of corroding soil anchors is developed in this methodology due to the attack of chlorides. The importance of using a system reliability–based (open full item for complete abstract)

Committee: Robert Liang Dr. (Advisor); Lan Zhang Dr. (Committee Member); Anil Patnaik Dr. (Committee Member); Guo-Xiang Wang Dr. (Committee Member); Chien-Chung chan Dr. (Committee Member) Subjects: Civil Engineering; Engineering; Geotechnology

MS, Kent State University, 2014, College of Arts and Sciences / Department of Earth Sciences

During the morning of October 8, 2011, a massive landslide caused severe damage to State Route 14 (SR 14) in Cedar Canyon, eight miles outside Cedar City, Utah. The landslide detached approximately 1.5 million cubic yards of material from the south side of the canyon, displaced parts of the road and covered the remainder of a 1200 ft (365 m) stretch of SR 14 under more than 100 ft (30 m) thick debris. The stratigraphy of the canyon where the landslide occurred includes the cliff-forming Tibbet Canyon Member of the Straight Cliffs Formation (limey sandstone) and the underlying slope-forming Tropic Formation (shale) and Dakota Formation (mudstone and sandstone with coal horizons), all Cretaceous in age. The landslide initiated in the Straight Cliffs Sandstone and propagated as a translational slide along the contact between the colluvial soil and the underlying bedrock. Utah Department of Transportation (UDOT) drilled three borings through the landslide material, placed slope inclinometers in the borings, and conducted a geophysical survey from the crest to the toe of the slide. I used detailed line survey and window mapping methods to collect orientation data for 186 discontinuities within the Straight Cliffs and Dakota Sandstones. Stereonet plots of discontinuity orientation data, generated by the DIPS software, revealed the presence of three principal joint sets that contribute to slope instability at the site. Samples of the colluvial soil and the bedrock were tested in the laboratory to determine relevant engineering properties including natural water content, density, and shear strength parameters (cohesion and friction) of soil, bedrock, and soil-bedrock contact. The SLIDE software program and data generated in the laboratory were used to perform a stability analysis which indicated a factor of safety of 0.8 to 1.2 for the dry conditions and 0.3 to 0.4 for fully saturated conditions (water table at ground level). A sensitivity analysis was performed by adjustin (open full item for complete abstract)

Committee: Abdul Shakoor (Advisor) Subjects: Geology; Geotechnology

MS, Kent State University, 2013, College of Arts and Sciences / Department of Earth Sciences

Mountain Lake is one of only two natural lakes in the state of Virginia. The lake's origin has been attributed to either a natural solution-collapse basin, or to a landslide damming the valley of northwesterly flowing Pond Drain, or to a NW-SE trending fracture lineation. The lake is located within the breached northwest limb of a gently plunging anticline, a part of the larger Valley and Ridge physiographic province. In recent years, the lake drained almost completely, exposing the lake bottom and revealing the presence of four sinkhole-like depressions, containing piping holes at their sides and bottoms, at the northeastern and northwestern margins of the lake. This study focuses on the most likely origin of large sandstone blocks present at the northern end of the lake in an area locally referred to as "Rock City", including mapping of the block locations and analyzing the mode and extent of displacement that they have undergone. An additional objective is to investigate the piping potential of the lake-bottom sediment and its role in seepage out of the lake basin causing lake-level fluctuations. Mapping of Rock City was conducted by taking GPS readings at the corners of the rock blocks and using ArcMap Software. Investigations of the displacement mode of the rock blocks was done by comparing the measured orientations of principal discontinuity sets, forming the rock-block boundaries, with discontinuity orientations of undisturbed outcrops within the headscarp, using stereonet analysis. Grain size analysis, Atterberg limits, and a compaction-mold permeameter test were used to evaluate lake sediment's susceptibility to piping. Field observations and discontinuity data analysis indicate that Rock City is a landslide that dammed the valley of Pond Drain, consequently forming the lake. The primary mode of slope movement involves lateral spreading that is associated with extension occurring along discontinuities. The Tuscarora Sandstone rock blocks comprising R (open full item for complete abstract)

Committee: Abdul Shakoor PhD (Advisor); Daniel Holm PhD (Committee Member); Neil Wells PhD (Committee Member) Subjects: Environmental Engineering; Environmental Geology; Geology; Geomorphology; Hydrologic Sciences

MS, University of Cincinnati, 2002, Engineering : Civil Engineering

A landslide occurred in the Greater Cincinnati, Ohio Area as a result of the development of an apartment complex which required the cutting of a slope toe by 20 or more feet. The property and development configuration disallowed replacement of the slope toe and the depth and height of the slide mass prevented the construction of a reasonable retaining system. The landslide was stabilized by installing a drainage system consisting of 15 horizontal pipe drains. The discussion includes the development of a conceptual drain design and outlines the installation, which included considerable field adjustments. The drain installation resulted in the rapid lowering of the groundwater table more than 10 feet from its observed level during the drier months when the drains were installed. Individual drain flowrates were noted to approach and exceed 100,000 gallons per day, and continue to flow at rates as high as 20,000 gallons per day. Short-term and long-term monitoring programs are discussed as well as lessons learned for future landslide study and correction with horizontal drains.

Committee: Dr. Mark Bowers (Advisor) Subjects: Engineering, Civil

Doctor of Philosophy, The Ohio State University, 2009, Civil Engineering

Damage caused by landslides exceeds $ 3 billion annually in the U.S and more than $ 10 billion each year worldwide, making losses attributed to landslides greater than any other natural disaster except hurricanes. Along with massive property loss, thousands people are killed and injured every year as the result of landslides. Potentially, much of this property damage and many of the injuries and deaths can be avoided with an operational landslide warning system. The goal of this research is to develop a wireless sensor network to predict the onset of landslides. The system will work by recording orientation changes from tiltmeters deployed on the surface of landslide prone slopes. Basic wired detection systems have been installed but, due to the high costs, monitoring systems can only cover a limited portion of a slope and requiring pre-existing knowledge of the most likely slide locations. Wireless landslide detection systems today have many problems limiting their practicality. Current limitations include subsurface sensor installation costs, high energy consumption and actual validation at the network level. In this research software having the capacity to interpret signals and generate failure alerts is being developed. To validate the above system, measured displacement data using wired extensometers from select sites are converted to tilt values and for the same sites, failure modes showing vector plots are generated using a numerical analysis program. These failure modes will be compared with various non critical movements. These comparisons related to surface movement patterns will provide essential characteristics for the stable landslide warning algorithm. For demonstration of this system, a slope with forty nodes consisting of eight columns and five rows is considered to be representative a typical hill slope. This demonstration shows how to implement the proposed algorithm based on a simple on and off sensor which will perform similarly to a tiltmeter. (open full item for complete abstract)

Committee: William Wolfe PhD (Advisor); Fabian Tan PhD (Committee Member); Tarunjit Butalia PhD (Committee Member) Subjects: Civil Engineering

Master of Science, The Ohio State University, 2009, Civil Engineering

As part of the Ohio Department of Transportation's (ODOT's) ongoing effort to solve engineering problems for the Ohio transportation system through research, The Ohio State University has undertaken a Bio-Engineering for Land Stabilization study under the direction of Professor Patrick J. Fox and Professor Emeritus T. H. Wu. Bioengineering is the use of vegetation for slope stabilization and has been used with success throughout the world; however, not much work on this topic has been performed in the mid-western United States. The aim of this study is to identify bioengineering methods to address ODOT's land stabilization needs in response to the all too common occurrence of shallow landslides. Bioengineering methods offer environmentally and economically attractive alternatives to traditional approaches to remediate and prevent such landslides. This research plans to achieve several objectives through the construction of three field demonstration projects: (1) to identify important factors that control success or failure of bioengineering methods, (2) to develop installation techniques and designs for successful application of bioengineering methods, (3) to provide thorough documentation to guide future work in bioengineering for ODOT, and (4) to develop new monitoring and testing methods that may be required for bioengineering projects. To date, research demonstration sites have been selected in Muskingum, Logan, and Union Counties and design and construction efforts are underway. Initial results of the project indicate that bioengineering installations, such as live willow poles, can be effective for the stabilization of shallow slides if the vegetation can be established.

Committee: Patrick Fox PhD (Advisor); Tien Wu PhD (Committee Co-Chair); William Wolfe PhD (Committee Member) Subjects: Civil Engineering

MS, Kent State University, 2011, College of Arts and Sciences / Department of Earth Sciences

The Pennsylvania Turnpike Commission plans to widen I-76 due to increased traffic in the Somerset County. The New Baltimore landslide, which has caused serious problems for the turnpike since its construction in 1939, is located within this area. The landslide extends 2000 feet (610 m) upslope and 1000 feet (305 m) laterally, and moves 5 to 10 inches (13 to 25 cm) per year. The Turnpike Commission plans to cut into the slope between mile markers 128 and 129 on the south side of the turnpike, thereby passing through the New Baltimore landslide. When the Pennsylvanian Turnpike is realigned, there could be new instability, reactivating the landslide and adding to instability. The bedrock geology of the New Baltimore landslide site consists of the Upper Devonian Catskill Formation which contains interbedded sequences of harder and softer strata including siltstone, shale, and grayish red sandstone units. This research project was conducted to determine the engineering properties of rocks and stability of the slope located between the mile markers mentioned above. A subsurface investigation was conducted on the New Baltimore landslide by the American Geotechnical and Environmental Services, Inc. of Pennsylvania. Field work was conducted to find the upper limit of the landslide and to collect discontinuity data. The discontinuity data were analyzed to evaluate various modes of slope failure. Lab work conducted in this study included the dry density test, slake durability test, unconfined compression test, and the shear strength test. The results of the study show that slake durability index of the claystone units ranges from 72 to 99% whereas the unconfined compressive strength of the sandstone/siltstone units ranges from 8,900 to 25,600 psi (61.4 to 176.5 MPa). Direct shear test results show that the claystone has a cohesion of 28,455 psf (1362 kPa) and a friction angle of 17 degrees. The inclinometer data shows that there is small movement along the weaker claystone u (open full item for complete abstract)

Committee: Abdul Shakoor Dr. (Advisor); Peter Dahl Dr. (Committee Chair); Joseph Ortiz Dr. (Committee Chair) Subjects: Geological; Geology

Master of Science (MS), Bowling Green State University, 2012, Geology

The purpose of this study was to detect shallow landslides using hillshade maps derived from Light Detection and Ranging (LiDAR)-based Digital Elevation Model (DEM) and validated by field inventory. The landslide susceptibility mapping used an Artificial Neural Network (ANN) approach and back propagation method that was tested in the northern portion of the Cuyahoga Valley National Park CVNP) located in Northeast Ohio. The relationship between landslides and different predictor attributes extracted from the LiDAR-based-DEM such as slope, profile and plan curvatures, upslope drainage area, annual solar radiation, and wetness index was evaluated using a Geographic Information System (GIS) based investigation. The approach presented in this thesis required a training study area for the development of the susceptibility model and a validation study area to test the model. The results from the validation showed that within the very high susceptibility class, a total of 42 % of known landslides that were associated with 1.6% of total area were correctly predicted. On the other hand, the very low susceptibility class that represented 82 % of the total area was associated with 1 % of correctly predicted landslides. The results suggest that the majority of the known landslides occur within a small portion of the study area, which is consistent with field investigation and other studies. Sample probabilistic maps of landslide susceptibility potential and other products from this approach are summarized and presented for visualization which is intended to help park officials in effective management and planning.

Committee: Peter Gorsevski PhD (Advisor); Charles Onasch PhD (Committee Member); Xinyue Ye PhD (Committee Member) Subjects: Geographic Information Science; Geology; Geomorphology

Doctor of Philosophy, University of Akron, 2011, Civil Engineering

One of the most common ways to stabilize the slope is to use the row of drilled shaft. The goal of this investigation is to introduce applicable methodology to calculate the factors of safety and force, on the shaft, in the static condition. By using the limit equilibrium approach accompanied with the concept of arching, due to incorporating the drilled shaft, the safety and force can be calculated. The 3-dimensional finite element parametric study is used to derive the regression based semi-empirical equations for quantifying the arching effect, through the load transfer factor. A computer program is written to incorporate the algorithms mentioned above for applications to real cases. The results of the proposed methodology are validated by the three dimension finite element analysis. Furthermore, seismic displacement of the slope, reinforced with a row of the drilled shafts, is calculated using modified displacement based method. This procedure is the extension work of seismic slope stability analysis presented by Bray and Rathje (1998) and Screen analysis presented by Stewart and Blake (2003). In this procedure, dynamic resistance of the dilled shaft/slope system is calculated in framework of limit equilibrium analysis accompanied with the arching due to incorporating the drilled shaft. To quantify the arching, the critical displacement is selected. First, the variation of arching as a function of displacement is studied. Then for critical displacement that causes the maximum force on the shaft and maximum displacement, the arching is quantified and applied to the limit equilibrium analysis. To address the geotechnical and structural issues, the performance based design is proposed to calculate the factor of safety of the drilled shaft slope system and the force on the drilled shafts based on an acceptable displacement. The results of seismic displacement, the factor of safety of slope shaft system, and the maximum induced force on the drilled shaft are validate (open full item for complete abstract)

Committee: Robert Liang Dr. (Advisor); Ali Hajjafar Dr. (Committee Member); Kallol Sett Dr. (Committee Member); Hamid Bahrami Dr. (Committee Member); Ala Abbas Dr. (Committee Member) Subjects: Engineering

Doctor of Philosophy, University of Akron, 2007, Civil Engineering

An accurate and practical methodology for stability analysis and design of drilled shafts reinforced slopes was developed utilizing limiting equilibrium method of slices. Complex soil stratifications and general failure slip surfaces can be handled in the developed method. The effect of soil arching due to the presence of the drilled shafts was accounted for by using a load transfer factor. The numerical values of the load transfer factor were developed based on 3-D FEM parametric study results. Many of the design variables controlling the slope/shaft systems, such: drilled shafts size, shafts location, shaft fixity (the necessary rock-socket length), and the required spacing between the drilled shafts to prevent soil from flowing around the shafts can be successfully determined from the developed method. The optimum location where the drilled shafts could be placed within the sliding soil mass so that the cost associated with the landslide repair using the drilled shafts is minimized can be searched for and determined from the developed methodology. From geotechnical point of view, the global factor of safety for slope/shaft systems can be determined. From structural point of view, the forces acting on the stabilizing drilled shafts due to the moving ground can be successfully estimated. In addition to the developed design methodology, Real-time instrumentation and monitoring were carried out for three landslide sites in the Southern part of Ohio. Various types of instruments were extensively installed inside the stabilizing shafts and the surrounding soils to monitor and better understand the behavior of slope/shaft systems. The UA Slope program developed by Dr. Robert Liang in corporation with ODOT and FHWA has been used in designing these landslides. The field instrumentation and monitoring processes have provided excellent and unique information on the lateral responses of shafts undergoing slope movements. Also, the results of the instrumented cases have provi (open full item for complete abstract)

Committee: Robert Liang (Advisor) Subjects: Engineering, Civil

Doctor of Philosophy, University of Akron, 2007, Civil Engineering

Landslides or slope/embankment failures along highways present potential safety and operational hazards. Road closures or detours due to the landslides impact the regional economy when services and commercial goods cannot be distributed to their destinations and the extra fuel and maintenance costs for additional mileages due to road detours. With the limited resources to the Ohio Department of Transportation (ODOT), it becomes imperative that a decision-making tool is developed to effectively manage the landslide hazards impacting highways in Ohio. The objective of this research study is to develop a landslide risk management system. An innovative web-enabled database, built upon GIS platform is developed for real-time managing of landslide spatial and temporal data. A landslide hazard rating system has been developed to provide a means to numerically score and rate the relative hazard or risk level of each site. The associated statistical and cluster analysis results of 37 Ohio landslide sites collected as a pilot database validates the effectiveness of the rating system. An alternative method to assist decision-making is also developed for managing the risks of potential highway slope failures. Usually, decision to manage risk on the failed highway project depends on many parameters. Some of them are based expert opinion and difficult to quantify and standardize. Relying only on expert experience may result in bias and irrational decision. In this dissertation, a method to deal with expert opinion was proposed. The linguistic fuzzy technique is used to transform the expert judgment into numerical values. The application of multi-criteria decision function standardizes the qualitative and quantitative parameters; therefore, the parameters (criteria) having different units can be combined. The importance of each risk parameter is determined using the factor analysis technique. It essentially involves the use of the best linear combination of the parameters to accou (open full item for complete abstract)

Committee: Robert Liang (Advisor) Subjects: Engineering, Civil; Geology