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Articles 91 - 120 of 158

Full-Text Articles in Geotechnical Engineering

Soil-Structure Interaction Effects On The Seismic Response Of Low-Rise Eccentrically Braced Frames, Luis Gerardo Buitrago Goyez Aug 2017

Soil-Structure Interaction Effects On The Seismic Response Of Low-Rise Eccentrically Braced Frames, Luis Gerardo Buitrago Goyez

Graduate Theses and Dissertations

The importance of soil-structure interaction (SSI) effects on the seismic response of buildings has been long recognized and has been researched for over 40 years. However, SSI analysis has only been applied in a few building projects because the fixed base condition is considered to provide a conservative estimation for the response of buildings under seismic loads. This assumption of a fixed base condition adopted by practitioners is not always conservative or cost-effective, especially for rigid buildings over soft soils. Additionally, for the case of ductile steel frames with eccentric configurations, the influence of SSI on their seismic performance has …


Laboratory Resistivity Measurements For Soil Characterization, Behdad Mofarraj Kouchaki Aug 2017

Laboratory Resistivity Measurements For Soil Characterization, Behdad Mofarraj Kouchaki

Graduate Theses and Dissertations

Field based electrical resistivity measurements, such as electrical resistivity tomography (ERT) and capacitively coupled resistivity (CCR), are geophysical methods that offer a non-destructive and rapid means to collect continuous data. As such, ERT and CCR are becoming increasingly popular tools for geotechnical engineers; however, it is challenging to derive geotechnical information such as soil type, density, and water content from the data. A laboratory geophysical investigation was carried out to gain a better understanding of the parameters that affect the electrical resistivity of soils and devise a relationship between resistivity and soil type or classification. In this study, a soil …


Geophysical Assessment Of Kinion Lake Dam, Tim Allen Moody Aug 2017

Geophysical Assessment Of Kinion Lake Dam, Tim Allen Moody

Graduate Theses and Dissertations

Geophysical methods including Capacitively-Coupled Resistivity (CCR), Electrical Resistivity Tomography/Imaging (ERT/ERI), Multichannel Analysis of Surface Waves (MASW) with Love and Rayleigh waves and a Full-Waveform Inversion (FWI) were performed on Kinion Lake Dam, an earth-filled embankment dam that has historically experienced significant seepage and internal erosion issues. Surveys were completed along the crest and downstream toe of the dam. Results from the surveys indicate that each method is capable of resolving the bedrock depth within 1-2 m of locations shown on previous drilling logs, though some discrepancies between the methods exist. A weathered bedrock layer is believed to have led to …


Development Of A Multiband Remote Sensing System For Determination Of Unsaturated Soil Properties, Cyrus D. Garner May 2017

Development Of A Multiband Remote Sensing System For Determination Of Unsaturated Soil Properties, Cyrus D. Garner

Graduate Theses and Dissertations

A multiband system including active microwave sensing and visible-near infrared reflectance spectroscopy was developed to measure unsaturated soil properties in both field and laboratory environments. Remote measurements of soil volumetric water content (θv), soil water matric potential (ψ), and soil index properties (liquid limit [LL], plastic limit [PL], and clay fraction [CF]) were conducted. Field-based measurement of θv was conducted using a ground-based radar system and field measurements within 10 percentage points of measurements acquired with traditional sampling techniques were obtained. Laboratory-based, visible and near infrared spectroscopy was found to be capable of obtaining empirical, soil specific regression functions (partial …


Resistivity Profiles Of Perth Soil In Australia In Leak-Detection Test, Lopa M. Pandey, Sanjay K. Shukla, Daryoush Habibi Jan 2017

Resistivity Profiles Of Perth Soil In Australia In Leak-Detection Test, Lopa M. Pandey, Sanjay K. Shukla, Daryoush Habibi

Research outputs 2014 to 2021

The use of a suitable leak-detection system for the prevention and mitigation of pollution due to lining system failures is integral to the proper management of landfill facilities. This paper briefly summarises various methods of leak detection that are currently being practised. The details of a newly developed leak-detection technique are also presented. The tests were conducted to evaluate the performance of the new technique by use of controlled leakage. The resulting resistivity profiles for Perth soil in Australia were obtained at 10 min. This method is found to be effective in detecting and locating liner leakage issues within 30 …


Assessment Of Rockfall Rollout Risk Along Varying Slope Geometries Using The Rocfall And Crsp Software, Mariam S. Al E'Bayat Jan 2017

Assessment Of Rockfall Rollout Risk Along Varying Slope Geometries Using The Rocfall And Crsp Software, Mariam S. Al E'Bayat

Masters Theses

"Most routes in mountainous areas suffer from rock falling, rolling and bouncing risk. There are many computer programs concerned with simulating the rockfall problem, and whereas they have the same purpose, they however differ in the input data that's needed to simulate the problem, and they also differ in the way of processing and kind of output.

This study used Rocfall® and the Colorado Rockfall Simulation Program (CRSP®) to simulate sixty-three models of varying slope geometry, where only the slope geometry is changed with the same material properties for both the slope and the rocks.

Both programs were fast and …


Imaging In Karst Terrain Using The Electrical Resistivity And Multichannel Analyses Of Surface Wave Methods, Ragab W. Jaafar Jan 2017

Imaging In Karst Terrain Using The Electrical Resistivity And Multichannel Analyses Of Surface Wave Methods, Ragab W. Jaafar

Masters Theses

"Electrical resistivity tomography and multi-channel analyses of surface waves data were acquired at a study area in Phelps County in the south-central part of Missouri. The objectives of the investigation were fourfold: 1) to image the subsurface in the study area to a depth of 70 feet; 2) to compare the ERT images generated using both the dipole-dipole and Wenner-Schlumberger arrays; and 3) to assess how variations in the MASW array configuration affected MASW data quality; and 4) to compare the ERT-estimated depth to top-of-rock and the MASW-generated depth to top-of-rock.

The subsurface in the study area was imaged to …


In-Situ Assessment Of Concrete Bridge Decks And Pavements Using Stress-Wave Based Methods, Mengxing Li Jan 2017

In-Situ Assessment Of Concrete Bridge Decks And Pavements Using Stress-Wave Based Methods, Mengxing Li

Doctoral Dissertations

"Concrete infrastructure of United States is aging and deteriorating. Accurate assessment the condition of concrete infrastructure is critical for its maintenance and rehabilitation. Stress-wave based methods, including ultrasonic surface wave (USW) and impact echo (IE), are becoming popular for characterizing defects and mechanical properties of concrete infrastructures. In this dissertation, a comprehensive literature review of seismic wave theory and common types of defects identified in concrete infrastructures, as well as stress-wave based methods used for concrete infrastructure monitoring and characterizing on a selected concrete bridge deck and two concrete pavement segments are present. The utility and reliability of both methods …


Soil Moduli Obtained From A Back Pressure Constant Rate Of Strain Bender Element Consolidation Apparatus, Yi Zhao Dec 2016

Soil Moduli Obtained From A Back Pressure Constant Rate Of Strain Bender Element Consolidation Apparatus, Yi Zhao

Graduate Theses and Dissertations

A back-pressure saturated, constant-rate-of-strain consolidation device was modified to incorporate bender elements (BP-CRS-BE) and thus allowed for shear wave measurements during consolidation tests. This newly fabricated system has many advantages over other previous or current devices: 1) it can be utilized not only for laboratory prepared soil samples but also for field sampled soils such as Shelby tube samples, and 2) continuous compression curves, and continuous values of vertical hydraulic conductivity and coefficient of consolidation can be acquired with a significant reduction in testing time. Soil modulus values such as shear modulus and constrained modulus are also able to be …


Geotechnical Properties Of The Travis Peak (Hosston) Formation In East Texas: A Compressive And Tensile Strength Analysis Using Regression Analysis., Pawan Kakarla Dec 2016

Geotechnical Properties Of The Travis Peak (Hosston) Formation In East Texas: A Compressive And Tensile Strength Analysis Using Regression Analysis., Pawan Kakarla

Electronic Theses and Dissertations

The estimation of rock mass strength is a key parameter in geotechnical engineering which is used in the design of geotechnical structures like tunnels, dams and slopes. Geotechnical engineering is the branch of civil engineering which works on the principles of soil and rock mechanics to evaluate subsurface conditions, stability of slopes, foundations of structures and construction of earthworks. The main focus of this study was to calculate the strength of Lower Cretaceous Travis Peak Formation rocks of East Texas and to check the accuracy by comparing it with Regression analysis. The parameters which were used were the Uniaxial Compression …


Characterization And Delineation Of Karst Geohazards Along Rm652 Using Electrical Resistivity Tomography, Culberson County, Texas, Adam F. Majzoub Dec 2016

Characterization And Delineation Of Karst Geohazards Along Rm652 Using Electrical Resistivity Tomography, Culberson County, Texas, Adam F. Majzoub

Electronic Theses and Dissertations

The Delaware Basin of West Texas and southeastern New Mexico is the major western subdivision of the Permian Basin and a northern extension of the Chihuahuan Desert. The major evaporite unit within the Delaware Basin is the Castile Formation, which consists of gypsum/anhydrite and is highly susceptible to dissolution and karsting. Manifestations of karst within the Castile outcrop are abundant and include sinkholes, subsidence features and caves, both epigene and hypogene in origin.

Land reconnaissance surveys conducted during the summer of 2015 documented abundant karst landforms in close proximity to a major thoroughfare, RM 652, in Culberson County, Texas. 2D …


Guidance Index For Shallow Landslide Hazard Analysis, Cheila Cullen Sep 2016

Guidance Index For Shallow Landslide Hazard Analysis, Cheila Cullen

Dissertations, Theses, and Capstone Projects

Rainfall-induced landslides are one of the most frequent hazards on slanted terrains. They lead to considerable economic losses and fatalities worldwide. Intense storms with high-intensity and long-duration rainfall have high potential to trigger rapidly moving soil masses due to changes in pore water pressure and seepage forces. Nevertheless, regardless of the intensity-duration of the rainfall, shallow landslides are influenced by antecedent soil moisture conditions. To the present day, no system exists that dynamically interrelates these two factors.

This work establishes a relationship between antecedent soil moisture and rainfall expressed in the form of a Shallow Landslide Index (SLI) at 1km …


Validation Of An Internal Camera Based Volume Determination System For Triaxial Testing, Leah D. Miramontes May 2016

Validation Of An Internal Camera Based Volume Determination System For Triaxial Testing, Leah D. Miramontes

Civil Engineering Undergraduate Honors Theses

Accurate strain and volume measurements are critical to phase relationships and strength determination for saturated and unsaturated soils. In recent years, laboratory-based photographic techniques of monitoring soil specimens have become more common. These techniques have been used to reconstruct 3D models and to determine strain and volumetric changes of triaxial specimens. A new technique that utilized digital photographs of the soil specimen, captured from within a triaxial testing cell, was utilized. Photographs were processed using photogrammetry software to reconstruct 3D models of the soil specimens. By placing camera equipment within the cell, the technique eliminated the need to account for …


Use Of Laboratory Geophysical And Geotechnical Investigation Methods To Characterize Gypsum Rich Soils, Raghava A. Bhamidipati Jan 2016

Use Of Laboratory Geophysical And Geotechnical Investigation Methods To Characterize Gypsum Rich Soils, Raghava A. Bhamidipati

Theses and Dissertations--Civil Engineering

Gypsum rich soils are found in many parts of the world, particularly in arid and semi-arid regions. Most gypsum occurs in the form of evaporites, which are minerals that precipitate out of water due to a high rate of evaporation and a high mineral concentration. Gypsum rich soils make good foundation material under dry conditions but pose major engineering hazards when exposed to water. Gypsum acts as a weak cementing material and has a moderate solubility of about 2.5 g/liter. The dissolution of gypsum causes the soils to undergo unpredictable collapse settlement leading to severe structural damages. The damages incur …


Imaging Reinforced Concrete: A Comparative Study Of Ground Penetration Radar And Rebarscope, Abhishek Kodi Jan 2016

Imaging Reinforced Concrete: A Comparative Study Of Ground Penetration Radar And Rebarscope, Abhishek Kodi

Masters Theses

"Geophysical techniques have been playing a very vital role in subsurface imaging in the recent past. Technology has been making it both reliable and convenient to utilize non-destructive geophysics techniques like Ground Penetration Radar, Induction current based Rebarscope, Seismic methods, ERT, etc. The applications range from shallow subsurface investigation of Bridge decks to old tunnels, mapping of rabars in a pre-existing construction and analyzing the concrete strength.

The thesis constitutes of a comparative study and analysis of a Ground Penetration Radar system and a Rebarscope. Individual parameters obtained directly from the study and obtained indirectly from the study shall be …


Building Codes To Minimize Cover Collapses In Sinkhole-Prone Areas, George Veni, Connie Campbell Brashear, Andrew Glasbrenner Oct 2015

Building Codes To Minimize Cover Collapses In Sinkhole-Prone Areas, George Veni, Connie Campbell Brashear, Andrew Glasbrenner

Sinkhole Conference 2015

Cover- collapse sinkholes are forming with increasing frequency under buildings. Analyses of sinkhole distribution in Beacon Woods, Florida, preliminarily indicate their occurrence is an order of magnitude greater in urban versus undeveloped areas, suggesting the structures themselves are enhancing the collapse process. The most likely causes are induced recharge via at least one of two sources. First, runoff and drainage from roads, structures, and impoundments that is not adequately dispersed will promote sinkhole development. Second, leaking water, sewer, and septic systems beneath or adjacent to a structure will also promote collapse. The process of cover-collapse from induced recharge is well …


A Method Of Mapping Sinkhole Susceptibility Using A Geographic Information System: A Case Study For Interstates In The Karst Counties Of Virginia, Alexandra L. Todd, Lindsay Ivey-Burden Oct 2015

A Method Of Mapping Sinkhole Susceptibility Using A Geographic Information System: A Case Study For Interstates In The Karst Counties Of Virginia, Alexandra L. Todd, Lindsay Ivey-Burden

Sinkhole Conference 2015

Karst terrain is landscape underlain by limestone that has been chemically dissolved by acidic groundwater, producing subsurface voids that pose risks for sinkholes if the overlaying soils can no longer support their own weight and collapse. The western counties of Virginia are heavy in karst due to their natural, geographic boundary of the western Ridge Province and the eastern Blue Ridge Mountain Range. As a result, the Commonwealth of Virginia Hazard Mitigation Plan recommends that the Virginia Department of Transportation (VDOT) develop a method to determine the roadways and regions most susceptible to experiencing sinkholes, in an effort to reduce …


Successful Foundation Preparations In Karst Bedrock Of The Masonry Section Of Wolf Creek Dam, David M. Robison Oct 2015

Successful Foundation Preparations In Karst Bedrock Of The Masonry Section Of Wolf Creek Dam, David M. Robison

Sinkhole Conference 2015

Extensive foundation preparations during construction of the Wolf Creek Dam concrete masonry section precluded the need for additional rehabilitation to mitigate seepage through karstic limestone bedrock. Wolf Creek Dam on the Cumberland River in southern Kentucky has become well known for karst related seepage issues underneath the embankment section, and yet has had little to no seepage issues associated with the concrete masonry portion of the dam. Post-construction efforts to control seepage underneath the embankment began in 1967 and 1968. Emergency grouting commenced and continued through 1970. Between 1975 and 1979 a more permanent solution of a concrete diaphragm cut-off …


Pre-Construction Rock Treatment And Soil Modification Program Using Low Mobility Grout To Mitigate Future Sinkhole Development In A 2,787.1 Square Meter (30,000 Sf) Maintenance Facility, Steven W. Shifflett Oct 2015

Pre-Construction Rock Treatment And Soil Modification Program Using Low Mobility Grout To Mitigate Future Sinkhole Development In A 2,787.1 Square Meter (30,000 Sf) Maintenance Facility, Steven W. Shifflett

Sinkhole Conference 2015

The US Army required construction of a 2,787.1 square meters (30,000 sf) maintenance facility supported on shallow foundations at the Fort Campbell Military Installation. During the subsurface investigation a seven foot air-filled void was encountered in the bedrock within the building footprint. Electrical Resistivity Imaging (ERI) was conducted in an attempt to determine the lateral extent of the encountered void and to establish the general prevalence of karst features at the site. Due to uncertainty in the subsurface conditions, a rock treatment and soil modification program was developed which consisted of a series of targeted exploratory grout holes advanced in …


Monitoring The Threat Of Sinkhole Formation Under A Portion Of Us 18 In Cerro Gordo County, Iowa Using Tdr Measurements, Kevin O'Connor, Matthew Trainum Oct 2015

Monitoring The Threat Of Sinkhole Formation Under A Portion Of Us 18 In Cerro Gordo County, Iowa Using Tdr Measurements, Kevin O'Connor, Matthew Trainum

Sinkhole Conference 2015

Sinkhole formation is a common occurrence in northeast Iowa, and U.S. 18 in Cerro Gordo County was constructed over an area where sinkhole formation had only been locally known. It had not been recorded or identified in the Iowa DNR database at the time. Since 2004, sinkholes have developed along the right of way. Geophysical surveys contributed very little in the identifying the cause. However a Soil Survey (drilling program) identified numerous voids within carbonate bedrock. The soil borings indicated that shale overlying the carbonate rock has been removed/eroded, and resulted in the development of a karst subsurface through the …


Seeps And Springs At A Platteville “Observatory” On The River Bluffs, Bj Bonin, Greg Brick, Julia R. Steenberg Oct 2015

Seeps And Springs At A Platteville “Observatory” On The River Bluffs, Bj Bonin, Greg Brick, Julia R. Steenberg

Sinkhole Conference 2015

Residential building construction along the Mississippi River bluffs in the 1970s created a unique enclosed outcrop of the Late Ordovician Platteville Formation at Lilydale, Minnesota. This outcrop was examined in early 2013 after a newly-formed spring flooded an elevator shaft the previous year, drawing attention to the foundation conditions. The Lexington Riverside property is a six story condominium complex constructed within the top of the bluff. A two-level underground parking garage was built into the bluff. Bedrock was mechanically excavated to accommodate the construction of the building, creating an unweathered rock surface. The space between the structure and the excavated …


Karst Spring Cutoffs, Cave Tiers, And Sinking Stream Basins Correlated To Fluvial Base Level Decline In South-Central Indiana, Garre A. Conner Oct 2015

Karst Spring Cutoffs, Cave Tiers, And Sinking Stream Basins Correlated To Fluvial Base Level Decline In South-Central Indiana, Garre A. Conner

Sinkhole Conference 2015

The Mitchell Aquifer averages 80m in thickness and underdrains a karst region in the Crawford Upland and Mitchell Plateau region in south-central Indiana (110,000 km2). The Springville Escarpment is a transitional boundary between the upland and plateau. Cave stream linking between cave tiers in the aquifer and correlation of cave tier inception horizons to a base level decline surface is interpreted for the Kirby Watershed, encompassing the prekarst headland of Indian Creek (42km2). The watershed was severed from lower Indian Creek at Eller Col by limestone cavern drainage on the ridge between White River and East Fork. Correlation of recharge …


Spatial Variability Of Subsurface Soil Conditions Causing Roadway Settlements, Ömer Bilgin, Kevin Arens, Mark Salveter, Alexander Dettloff Oct 2015

Spatial Variability Of Subsurface Soil Conditions Causing Roadway Settlements, Ömer Bilgin, Kevin Arens, Mark Salveter, Alexander Dettloff

Civil and Environmental Engineering and Engineering Mechanics Faculty Publications

Settlement of problematic soils constituting the roadway subgrade may result in pavement distress and structural failure, requiring periodic pavement patching and resurfacing. Many of these problems occur as a result of the settlement of soft cohesive and organic soils. Due to the extent of roadway projects and the limited frequency of boring locations, spatial variability of subsurface soil conditions, and sometimes due to an inadequate extent of exploration, these problematic soils may not be identified suitably during subsurface explorations. An extensive subsurface exploration program was implemented for detailed characterization of subsurface conditions for a relatively short section of an existing …


Multi-Component Active Source Rayleigh Wave Analysis, Gabriel Gribler Aug 2015

Multi-Component Active Source Rayleigh Wave Analysis, Gabriel Gribler

Boise State University Theses and Dissertations

Determining how a building site will respond to earthquake ground shaking plays a critical role in proper construction practices. One critical constraint on how a site responds is the near surface shear wave seismic velocity distribution. One commonly used method for indirectly estimating shear wave velocities is Multichannel Analysis of Surface Waves (MASW), which utilizes a spread of vertical geophones to measure Rayleigh wave dispersion. With this approach, phase velocity vs. frequency dispersion curve picks can be used to estimate shear wave velocities with depth. I investigate the use of two (vertical and horizontal inline) component seismic signals to record …


Interface Friction Parameters For The Mathematical Modeling Of Shell Structures With Infill, Alexander T. Bekker, Nikita Ya. Tsimbelman, Tatiana I. Chernova, Vadim D. Bruss, Ömer Bilgin Jun 2015

Interface Friction Parameters For The Mathematical Modeling Of Shell Structures With Infill, Alexander T. Bekker, Nikita Ya. Tsimbelman, Tatiana I. Chernova, Vadim D. Bruss, Ömer Bilgin

Civil and Environmental Engineering and Engineering Mechanics Faculty Publications

Thin metal or reinforced concrete shells with granular infill structures are considered in this article. These structures are massive and they are used as support for the construction of berthing quays, piers, artificial islands, shore protection, and other structures of coastal infrastructure. It is more convenient to use the thin shell structures during the development of the Arctic shelf, because it is possible to install them from the ice side. In addition, it is possible to enhance the technology and install thin shells with infill on deeper solid foundation layers. A mathematical model for the stresses on a compressible foundation …


Feasibility Study: The Evaluation Of Polymer Coatings To Prevent Weathering Of Weak Rocks, Lauren Distler May 2015

Feasibility Study: The Evaluation Of Polymer Coatings To Prevent Weathering Of Weak Rocks, Lauren Distler

Senior Honors Projects, 2010-2019

The weathering and erosion of weak rocks along roadways can cause dangerous and potentially fatal rockfalls.   Various slope stabilization methods exist, but each presents a set of challenges and trade-offs.   The focus of the project is to understand the feasibility of utilizing of a polymerbased slope stabilization technique. Rock samples were collected along US Route 33 in Virginia and West Virginia, and preliminary tests were conducted to evaluate the absorption of water (% mass) and durability. The study evaluates three polymer options in regard to the following criteria: adhesion to rock, layer thickness, semi-permeability, insolubility, and non-toxicity. The polymer selection …


Commercialization Of A Small, Lightweight, Low-Cost Seismic Borehole Receiver, Rachel Adams Jan 2015

Commercialization Of A Small, Lightweight, Low-Cost Seismic Borehole Receiver, Rachel Adams

Theses and Dissertations--Civil Engineering

Herein, conceptualization of a recently patented seismic borehole receiver and its components is developed for commercialization. The device is significantly cheaper, lighter, and smaller than existing technologies on the market. Additionally, it has the potential to achieve better seismic readings than its competitors via patented sensor-to-borehole coupling mechanism. It is the hope that the commercialization of this device will not only provide a more affordable alternative to engineers and geophysicists in the existing market, but the significant cost difference may open new seismic measurement opportunities in the developing world. Its compact size and light weight will increase mobility, allowing investigators …


Evaluating Methods Of Field-Based 3d Visualization And Their Application To Mapping Metamorphic Terranes: An Example From The Panamint Mountains, California, Jade Ashley Brush Jan 2015

Evaluating Methods Of Field-Based 3d Visualization And Their Application To Mapping Metamorphic Terranes: An Example From The Panamint Mountains, California, Jade Ashley Brush

Open Access Theses & Dissertations

Field geology has traditionally relied on 2D, paper-based workflows, but digital mapping techniques are rapidly replacing these outdated methods because they allow for more efficient and accurate mapping. This research applies digital mapping techniques and two terrestrially-based 3D visualization technologies, photogrammetry and Light Detection and Ranging (LiDAR), to the study of metamorphic terranes in the Panamint Mountains, California. This study reports on the spatial accuracy of TINs (triangulated irregular networks) generated from both photogrammetry and ground-based LiDAR using a terrestrial laser scanner (TLS) and discusses how spatial accuracy can be increased. Two levels of comparison were used to test spatial …


Field-Obtained Soil Water Characteristic Curves And Hydraulic Conductivity Functions, Elvis Ishimwe Aug 2014

Field-Obtained Soil Water Characteristic Curves And Hydraulic Conductivity Functions, Elvis Ishimwe

Graduate Theses and Dissertations

A compacted clay liner (test pad) was constructed and instrumented with volumetric water content and soil matric potential sensors to determine soil water characteristic curves (SWCC) and hydraulic conductivity (k) functions. Specifically, the compacted clay liner was subjected to an infiltration cycle during a sealed double ring infiltrometer (SDRI) test followed by a drying cycle. After the drying cycle, Shelby tube samples were collected from the compacted clay liner and flexible wall permeability (FWP) tests were conducted on sub-samples to determine the saturated hydraulic conductivity. Moreover, two computer programs (RETC and UNSAT-H) were utilized to model the SWCCs and k-functions …


Finite Difference Modeling Of Surface-~Wave Scattering For Shallow Cavity Detection, Heston Travis Norcott May 2014

Finite Difference Modeling Of Surface-~Wave Scattering For Shallow Cavity Detection, Heston Travis Norcott

UNLV Theses, Dissertations, Professional Papers, and Capstones

Data collection and analysis of scattering of Rayleigh-type surface waves are investigated for locating shallowly buried cavities. Surface-based seismic experiments conducted by others at the University of Nevada, Las Vegas (UNLV) Engineering Geophysics Test Site (EGTS) demonstrate scattering of Rayleigh waves caused by buried empty barrels (essentially air-filled cavities). The interpretation of the data is complicated by factors such as the presence of a high-velocity geologic layer just below the cavity.

This research uses a finite-difference seismic wave propagation code to compute time histories for a model that represents the Engineering Geophysics Test Site. By adding cavities to a background …