Settlement of roadway pavement surfaces near highway bridge abutments often leads to abrupt grade... more Settlement of roadway pavement surfaces near highway bridge abutments often leads to abrupt grade differences at the abutments. These grade differences subject vehicles to a "bump", which leads to driver discomfort and potentially unsafe driving conditions. In addition, differential movement causes vehicle wear, damages sensitive cargo, subjects the bridge to repeated impact loads, and requires costly and repeated maintenance work that usually impedes the flow of traffic. The objectives of the research described in this report were to: 1) review methods for reducing long-term deformations at the approach embankment/bridge interface and rehabilitating differential deformations; 2) quantify the magnitude of differential settlement/heave problems at the approach embankment/bridge interface in Illinois; 3) determine the factors that lead to differential movement at the approach embankment/bridge interface in Illinois; 4) review current Illinois Department of Transportation (IDOT) procedures for mitigating differential settlement; 5) review current IDOT maintenance/rehabilitation methods for the approach embankment/bridge interface; and 6) provide recommendations for reducing long-term deformations at the approach embankment/bridge interface in Illinois.
Understanding the runout of slope failures is important for hazard identification, risk assessmen... more Understanding the runout of slope failures is important for hazard identification, risk assessments, and disaster prevention. This study evaluates the accuracy of three runout software packages, DAN3D, Anura3D, and FLO-2D, for modeling the runout of the 2014 Oso landslide and investigates the viability of predicting the runout of other landslides and slope failures under similar conditions. The Oso landslide runout analyses using Anura3D and FLO-2D conducted for this study adopt the geotechnical conditions and failure mechanism reported by Stark and his colleagues in 2017. Together with DAN3D and Anura3D modeling reviewed from previous studies, the accuracy and applicability of these runout models are assessed using field observations. These analyses show the importance of (i) using a digital terrain model in the runout analysis, (ii) modeling field representative shear strength properties and failure mechanisms, and (iii) predicting runout distance, splash height, and duration for ...
This paper reviews the creep ratio concept suggested by Lane (1934) and added new case histories ... more This paper reviews the creep ratio concept suggested by Lane (1934) and added new case histories to expand his database. Lane (1934) selected conservative values of safe creep ratios because of the small number of dam failures in his database, which is prudent. The safe creep ratios recommended in this paper for “Gravel and Sand”, “Boulders, Gravel, and Sand”, and broadly-graded soils are believed to be a conservative interpretation of the available data. As Lane’s recommended values appear to be somewhat subjective, considerable engineering judgment is recommended in designing a dam for safety against piping, and Lane’s values are a starting point for design, rather than values for a final design.
This paper presents a conceptual model of tie-ballast interaction for high-speed passenger and fr... more This paper presents a conceptual model of tie-ballast interaction for high-speed passenger and freight railroads. The main components of the model are inclusion of a gap between the tie bottom and underlying ballast and a cubic function to model the tie-ballast load-displacement behavior. Field measurements from high-speed passenger and freight railroads were used to develop and verify the model and show tie-ballast gaps exist at every instrumented site. As a result, the main questions for railroad personnel are whether or not: (1) the tie-ballast gap is large enough to cause detrimental load redistribution amongst adjacent ties and (2) will the gap increase with additional traffic causing further load redistribution and gaps to develop under adjacent ties. Substructure load-displacement behavior is also used to estimate track modulus for use in numerical analyses of track transitions to evaluate design and repair options.
Copyright 2005 GFR Magazine. Reprinted with permission of Industrial Fabrics Association Internat... more Copyright 2005 GFR Magazine. Reprinted with permission of Industrial Fabrics Association International. 1 Thermal welding of polyvinyl chloride (PVC) geomembranes is an efficient and cost-effective method of field seaming. PVC geomembranes possess excellent thermal welding characteristics, such as a wide thermal seaming range and a lack of residual stresses or stress cracking. Also, as if with materials such as high-density polyethylene geomembrane, there is no required surface preparation (e.g., grinding). Fully automated welding systems can thermally weld PVC geomembranes as thin as 0.5 mm (20 mil). These welding systems allow the operator to adjust welding speed, nip-roller pressure, and welding temperature to create the best quality singleor dual-track thermal seams. This facilitates field seaming, though PVC geomembranes already call for as many as 80% fewer field seams than for polyethylene geomembranes. PVC affords the installation contractor the luxury of using three proven ...
This article describes a case history that illustrates a number of important design, specificatio... more This article describes a case history that illustrates a number of important design, specification, and bidding issues for landfill covers. The case history involves a landfill near Somerset County, Maryland in the beautiful coastal lands of the Chesapeake Bay. The landfill operated from 1977 to 1998 until the first cell of the adjacent new lined landfill opened. The closed site consists of about 30 acres. The landfill site is flat, sandy, with groundwater near the surface. The landfill is unlined and does not posses a leachate collection and removal system below the waste and thus installation of a final cover system is important to reduce groundwater contamination. The Code of Maryland Regulations (COMAR), issued by the Maryland Department of the Environment (MDE), require a minimum of 24 in. of interim soil cover prior to final closure. COMAR also require slopes to be 3H:1V or less and a low permeability layer, i.e., a geomembrane, in the final cover system to reduce infiltration.
The excess pore water pressure developed in the Upper San Fernando Dam during the 1971 San Fernan... more The excess pore water pressure developed in the Upper San Fernando Dam during the 1971 San Fernando Earthquake has been evaluated in several studies. Almost all of these studies indicate large excess pore pressure ratios developed only in the upstream and downstream shells which are not consistent with the limited deformation of the dam and the piezometer responses during the earthquake. In this paper, the construction and field observations of the behavior of the Upper San Fernando Dam are reviewed and a simple approach involving Newmark’s (1965) and Makdisi-Seed’s (1978) permanent deformation and limit equilibrium slope stability analyses are used to estimate the excess pore water pressures developed in the core and downstream shell areas during the earthquake for comparison with field measurements. The major differences of this analysis with previous studies lies in the assumptions regarding the selection of the failure plane, liquefiable zones, and mobilized shear strengths. The...
: The main objective of this research was to characterize the drained and undrained stress-strain... more : The main objective of this research was to characterize the drained and undrained stress-strain behavior of normally consolidated silts and clayey- silts. The results of this research were also used to develop a database of hyperbolic stess-strain and Mohr-Coulomb strength parameters for silts and clayey-silts. This research involved extensive drained and undrained triaxial tests on silt specimens with varying clay contents. The percentages of clay used in the silt mixtures were 0, 10, 30, and 50%. The effect of density was investigated by compacting the triaxial test specimens at Standard Proctor relative compactions of 85, 90, 95, and 100%. This report summarizes the test results and the resulting hyperbolic stress-strain and Mohr-Coulomb strength parameters for the various silt mixtures considered.
Refined relationships between cone penetration tip resistance and liquefaction resistance of sand... more Refined relationships between cone penetration tip resistance and liquefaction resistance of sandy soils are presented to facilitate use of the cone penetration test (CPT) in liquefaction studies. The proposed relationships are based on a database of field case histories where CPTs were performed and adjacent borings were drilled and sampled to confirm soil type and fines content. The newly-developed database employs stringent selection criteria to minimize inconsistencies in CPT sounding selection and interpretation that are present in other level-ground liquefaction databases, as well as to aid in the addition of data by others. Applying these proposed stringent criteria results in a reduced, but more defensible, database. Additionally, the effect of fines content on liquefaction resistance is quantified by a fines content adjustment in a form that facilitates use in practice.
U.S. landfill slope failure occurred in Ohio. Smaller incidents have been associated with earthqu... more U.S. landfill slope failure occurred in Ohio. Smaller incidents have been associated with earthquakes [See picture of slope failure on page 83]. It’s important to understand static and seismic slope stability, and how to handle a failure. For example, if a liner is damaged, the waste above that area must be removed and a new liner must be installed. A cover failure requires reinstallation. When a large quantity of waste becomes unstable, it must be moved over the lined area and re-covered. These remedial actions are expensive.
Settlement of roadway pavement surfaces near highway bridge abutments often leads to abrupt grade... more Settlement of roadway pavement surfaces near highway bridge abutments often leads to abrupt grade differences at the abutments. These grade differences subject vehicles to a "bump", which leads to driver discomfort and potentially unsafe driving conditions. In addition, differential movement causes vehicle wear, damages sensitive cargo, subjects the bridge to repeated impact loads, and requires costly and repeated maintenance work that usually impedes the flow of traffic. The objectives of the research described in this report were to: 1) review methods for reducing long-term deformations at the approach embankment/bridge interface and rehabilitating differential deformations; 2) quantify the magnitude of differential settlement/heave problems at the approach embankment/bridge interface in Illinois; 3) determine the factors that lead to differential movement at the approach embankment/bridge interface in Illinois; 4) review current Illinois Department of Transportation (IDOT) procedures for mitigating differential settlement; 5) review current IDOT maintenance/rehabilitation methods for the approach embankment/bridge interface; and 6) provide recommendations for reducing long-term deformations at the approach embankment/bridge interface in Illinois.
Understanding the runout of slope failures is important for hazard identification, risk assessmen... more Understanding the runout of slope failures is important for hazard identification, risk assessments, and disaster prevention. This study evaluates the accuracy of three runout software packages, DAN3D, Anura3D, and FLO-2D, for modeling the runout of the 2014 Oso landslide and investigates the viability of predicting the runout of other landslides and slope failures under similar conditions. The Oso landslide runout analyses using Anura3D and FLO-2D conducted for this study adopt the geotechnical conditions and failure mechanism reported by Stark and his colleagues in 2017. Together with DAN3D and Anura3D modeling reviewed from previous studies, the accuracy and applicability of these runout models are assessed using field observations. These analyses show the importance of (i) using a digital terrain model in the runout analysis, (ii) modeling field representative shear strength properties and failure mechanisms, and (iii) predicting runout distance, splash height, and duration for ...
This paper reviews the creep ratio concept suggested by Lane (1934) and added new case histories ... more This paper reviews the creep ratio concept suggested by Lane (1934) and added new case histories to expand his database. Lane (1934) selected conservative values of safe creep ratios because of the small number of dam failures in his database, which is prudent. The safe creep ratios recommended in this paper for “Gravel and Sand”, “Boulders, Gravel, and Sand”, and broadly-graded soils are believed to be a conservative interpretation of the available data. As Lane’s recommended values appear to be somewhat subjective, considerable engineering judgment is recommended in designing a dam for safety against piping, and Lane’s values are a starting point for design, rather than values for a final design.
This paper presents a conceptual model of tie-ballast interaction for high-speed passenger and fr... more This paper presents a conceptual model of tie-ballast interaction for high-speed passenger and freight railroads. The main components of the model are inclusion of a gap between the tie bottom and underlying ballast and a cubic function to model the tie-ballast load-displacement behavior. Field measurements from high-speed passenger and freight railroads were used to develop and verify the model and show tie-ballast gaps exist at every instrumented site. As a result, the main questions for railroad personnel are whether or not: (1) the tie-ballast gap is large enough to cause detrimental load redistribution amongst adjacent ties and (2) will the gap increase with additional traffic causing further load redistribution and gaps to develop under adjacent ties. Substructure load-displacement behavior is also used to estimate track modulus for use in numerical analyses of track transitions to evaluate design and repair options.
Copyright 2005 GFR Magazine. Reprinted with permission of Industrial Fabrics Association Internat... more Copyright 2005 GFR Magazine. Reprinted with permission of Industrial Fabrics Association International. 1 Thermal welding of polyvinyl chloride (PVC) geomembranes is an efficient and cost-effective method of field seaming. PVC geomembranes possess excellent thermal welding characteristics, such as a wide thermal seaming range and a lack of residual stresses or stress cracking. Also, as if with materials such as high-density polyethylene geomembrane, there is no required surface preparation (e.g., grinding). Fully automated welding systems can thermally weld PVC geomembranes as thin as 0.5 mm (20 mil). These welding systems allow the operator to adjust welding speed, nip-roller pressure, and welding temperature to create the best quality singleor dual-track thermal seams. This facilitates field seaming, though PVC geomembranes already call for as many as 80% fewer field seams than for polyethylene geomembranes. PVC affords the installation contractor the luxury of using three proven ...
This article describes a case history that illustrates a number of important design, specificatio... more This article describes a case history that illustrates a number of important design, specification, and bidding issues for landfill covers. The case history involves a landfill near Somerset County, Maryland in the beautiful coastal lands of the Chesapeake Bay. The landfill operated from 1977 to 1998 until the first cell of the adjacent new lined landfill opened. The closed site consists of about 30 acres. The landfill site is flat, sandy, with groundwater near the surface. The landfill is unlined and does not posses a leachate collection and removal system below the waste and thus installation of a final cover system is important to reduce groundwater contamination. The Code of Maryland Regulations (COMAR), issued by the Maryland Department of the Environment (MDE), require a minimum of 24 in. of interim soil cover prior to final closure. COMAR also require slopes to be 3H:1V or less and a low permeability layer, i.e., a geomembrane, in the final cover system to reduce infiltration.
The excess pore water pressure developed in the Upper San Fernando Dam during the 1971 San Fernan... more The excess pore water pressure developed in the Upper San Fernando Dam during the 1971 San Fernando Earthquake has been evaluated in several studies. Almost all of these studies indicate large excess pore pressure ratios developed only in the upstream and downstream shells which are not consistent with the limited deformation of the dam and the piezometer responses during the earthquake. In this paper, the construction and field observations of the behavior of the Upper San Fernando Dam are reviewed and a simple approach involving Newmark’s (1965) and Makdisi-Seed’s (1978) permanent deformation and limit equilibrium slope stability analyses are used to estimate the excess pore water pressures developed in the core and downstream shell areas during the earthquake for comparison with field measurements. The major differences of this analysis with previous studies lies in the assumptions regarding the selection of the failure plane, liquefiable zones, and mobilized shear strengths. The...
: The main objective of this research was to characterize the drained and undrained stress-strain... more : The main objective of this research was to characterize the drained and undrained stress-strain behavior of normally consolidated silts and clayey- silts. The results of this research were also used to develop a database of hyperbolic stess-strain and Mohr-Coulomb strength parameters for silts and clayey-silts. This research involved extensive drained and undrained triaxial tests on silt specimens with varying clay contents. The percentages of clay used in the silt mixtures were 0, 10, 30, and 50%. The effect of density was investigated by compacting the triaxial test specimens at Standard Proctor relative compactions of 85, 90, 95, and 100%. This report summarizes the test results and the resulting hyperbolic stress-strain and Mohr-Coulomb strength parameters for the various silt mixtures considered.
Refined relationships between cone penetration tip resistance and liquefaction resistance of sand... more Refined relationships between cone penetration tip resistance and liquefaction resistance of sandy soils are presented to facilitate use of the cone penetration test (CPT) in liquefaction studies. The proposed relationships are based on a database of field case histories where CPTs were performed and adjacent borings were drilled and sampled to confirm soil type and fines content. The newly-developed database employs stringent selection criteria to minimize inconsistencies in CPT sounding selection and interpretation that are present in other level-ground liquefaction databases, as well as to aid in the addition of data by others. Applying these proposed stringent criteria results in a reduced, but more defensible, database. Additionally, the effect of fines content on liquefaction resistance is quantified by a fines content adjustment in a form that facilitates use in practice.
U.S. landfill slope failure occurred in Ohio. Smaller incidents have been associated with earthqu... more U.S. landfill slope failure occurred in Ohio. Smaller incidents have been associated with earthquakes [See picture of slope failure on page 83]. It’s important to understand static and seismic slope stability, and how to handle a failure. For example, if a liner is damaged, the waste above that area must be removed and a new liner must be installed. A cover failure requires reinstallation. When a large quantity of waste becomes unstable, it must be moved over the lined area and re-covered. These remedial actions are expensive.
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