Timothy D. Stark

University of Illinois, Urbana-Champaign | UIUC · Department of Civil and Environmental Engineering

Current regulations require locations of noncompliant ballast to be remediated within 30 days or to be taken out of service, regardless of track class. In 2013, the Association of American Railroads (AAR) applied for a waiver to the current regulations that proposed a track class specific approach to managing noncompliant ballast. In 2015, the Fede...

This paper investigates the static and cyclic characteristics of a fouled sub-ballast material using static and cyclic triaxial tests. Static triaxial tests were conducted first to determine the peak strength, which was used as the applied stress in the cyclic tests. Moreover, the results of the displacement-controlled static triaxial test were use...

This paper presents a comparison of four (4) assumptions or approaches for using a liquefied shear strength ratio for sandy soils in cases where there has been a large increase in effective vertical stress, e.g., structure raising or remedial measure, that is outside the effective stresses of the case histories used to develop the empirical liquefi...

This technical paper presents a unique comparison of geomembrane factory and field welded thermal seams for a large off-stream water reservoir project. The results of the comparison show that factory welded seams exhibit higher seam peel and shear strengths at yield, less variability, and more consistency than field welded thermal seams. In particu...

The Caminada Headlands is a beach and dune system that provides natural protection for back barrier marshes against storm surges and wave overtopping. Due to significant shoreline erosion and regional subsidence, a beach and dune restoration project was initiated in 2012 to replenish the shoreline front. Because of the underlying soft deltaic sedim...

Levees and floodwalls providing risk reduction to major urban cities along the Mississippi River are prone to sand boils due to underlying alluvial sand foundations. This paper presents a case study for a levee embankment in Baton Rouge, Louisiana, where field measurements were used to determine the hydraulic properties of unsaturated soils incorpo...

A highway bridge spanning an at-grade railroad right-of-way was designed using two MSE wall supported abutments. The earthwork included the soil approach embankment and the MSE wall sand backfill. Steel H-piles were inserted through the backfill in corrugated metal pipes and then driven to the desired depth to support the bridge abutments. Before c...

This paper presents multi-layer interface shear test results for composite liner systems from fourteen landfill projects in California. The multi-layer configuration utilizes site-specific materials including low-hydraulic conductivity compacted soil (CSL), geosynthetic materials [geosynthetic clay liner (GCL), geomembrane (GM), drainage geocomposi...

Coastal barrier islands are the first line of defense for protecting wetlands, inland bays, and mainland regions from direct effects of wind, waves, and storms. Rosati (2006) indicate that 20 to 40% of the total sand volume can be sequestered and lost from the sandy barrier island through consolidation. As a result, predicting long-term subsurface...

en Geosynthetics are man‐made products manufactured to meet specific functions in earthworks and geotechnical projects, such as dams, levees, canals, dikes and other structures commonly found in agricultural engineering. Thanks to the Memorandum of Understanding between the International Geosynthetics Society (IGS) and the International Commission...

Data from track monitoring locations at bridge-track transitions that highlight some of the main contributing factors to excessive settlement and rapid track geometry deterioration.

Instrumentation and results from a long term evaluation of track degradation associated with fouled ballast.

Data from track settlement monitoring conducted at bridge-track transitions highlighting main factors observed to contribute to increased settlement and more rapid degradation

Lightweight fill materials, including foamed glass aggregates are increasingly being used in civil engineering and infrastructure applications in the U.S. The energy saving assessments have proven that the use of foamed recycled glass as engineering material has much lower energy consumption relative to a conventional aggregate-cement material. How...

Rapid drawdown is an important condition controlling the design of the upstream slope in embankment dams and levees. This paper presents the upstream slope failure at San Luis Dam as a case study for performing effective stress drawdown stability analyses. In effective stress analyses, stress-dependent drained shear strengths were used for the fine...

This case study describes failure of an interstate connecting-ramp embankment during construction and investigates performance of the prefabricated vertical drains (PVDs) installed to accelerate consolidation of the weak embankment foundation soils. The weak, fine-grained foundation soil experienced less drainage, and thus less consolidation and st...

This case study describes the failure of an interstate connecting-ramp embankment during construction and investigates the failure mechanism, performance of the prefabricated vertical drains (PVDs) installed to accelerate consolidation of the weak embankment foundation soils, embankment shear strength parameters, and design slope stability analyses...

This paper and presentation will provide survey results of fouled ballast definitions, parameters, limits/standards, and laboratory test results to assist in the creation of a straightforward procedure to measure fouling parameters based on track performance and safety. Federal Track Safety Standards (FTSS) for ballast are set forth under §213.103...

Many locations of railroad track consist of abrupt changes in track stiffness and underlying substructure called transition zones. These regions historically experience greater track settlement than the surrounding track re-quiring more frequent track maintenance from railroad companies. This paper emphasizes how discontinuities at the tie-ballast...

This paper describes and explains the spectacular mobility of the 2014 Oso landslide, which was the cause of its fatal consequences. A geomorphic interpretation of the site conditions is used to reconstruct the landslide failure mechanism. Two numerical models are used to conduct an inverse runout analysis. The models implement a newly defined rheo...

Geotechnical engineers understand there is uncertainty and risk in the input parameters for slope stability analyses and within the analysis methodologies themselves. Decades of research and inverse analyses of slope failures have resulted in widespread acceptance of certain factors of safety (FS) in typical situations, e.g., a static two-dimension...

Present 3D limit equilibrium (LE) methods do not incorporate shear resistance from near vertical sides parallel to the direction of slide movement. Consequently, the computed 3D factor of safety (FS) is underestimated and the shear strength parameters from an inverse analysis are overestimated. The present study uses continuum mechanics to calculat...

This paper presents a modified constitutive model to predict post-construction movements of compacted fills due to wetting based on the results of anisotropically-consolidated undrained (ACU) triaxial compression tests. The constitutive model is coded in the FISH language of the finite difference numerical software FLAC. The model allows deformatio...

Waste containment facilities can experience elevated temperatures for a variety of reasons such as hydration of combustion ash, aerobic biodegradation, and smoldering combustion. Elevated temperatures can reduce service life or effectiveness of geomembranes by accelerating antioxidant depletion and polymer degradation. A case history is presented t...

This paper presents a unique comparison of single and multi-layer interface shear strength tests for a recently constructed landfill liner system. The comparison includes peak and large displacement combination strength envelopes from single- and multi-layer interface direct shear tests for the same geomembrane (GM)/ drainage geocomposite (GC), geo...

Elevated temperatures in municipal solid waste landfills can pose health, environmental, and safety risks because they can generate excessive gases, liquids, pressures, and heat that can damage landfill infrastructure. This paper discusses mechanisms that can lead to elevated temperatures in the landfill and presents a case history to establish tre...

This paper describes the use of Spectral Analysis of Surface Wave (SASW) for characterizing rail track ballast and foundation layers. Surface wave testing on a rail track is more complicated than on soil sites or pavements due to the presence of large ballast void spaces, crossties, and rails as well as the complex variation of shear-wave velocity...

This paper uses the results of an extensive subsurface investigation performed along the Inner Harbor Navigational Canal in New Orleans, Louisiana to identify the scale effect of soil hydraulic conductivity (K) and compressibility (mv) for geotechnical and geoenvironmental analyses. The magnitude and variability of soil hydraulic conductivity and c...

This paper describes investigation, testing, analysis, and slope history used to determine the two-phase failure mechanism involved in the 2014 landslide near Oso, Washington. The first phase involves a slide mass located above the frequent landslides in the lower portion of the slope and extends to near the slope crest. This slide mass had a large...

Track support is necessary for reliable, resilient railroad track infrastructure. Ability to recover quickly from adversity is a hallmark of the railway industry, and ability to rapidly restore track to service is a main element contributing to resilience of rail service. Poor track support conditions can increase dynamic and impact loading on trac...

Elevated temperatures in waste containment facilities can pose health, environmental, and safety risks because they generate toxic gases, pressures, leachate, and heat. In particular, MSW landfills undergo changes in behavior that typically follow a progression of indicators, e.g., elevated temperatures, changes in gas composition, elevated gas pre...

This paper uses the San Luis Dam upstream slide to evaluate the pore-water pressures at failure and progression of the phreatic surface through the fine-grained core for drawdown stability analyses. The hydraulic conductivity and compressibility parameters of saturated and unsaturated soils are calibrated using the reservoir hydrograph and 13 piezo...

Sediment (mud and sand) from man-made diversions of the Mississippi River, dredging effluent, and other sources is being used to conserve and create land to protect the Gulf Coast. The long-term settlement prediction of these newly deposited sediments is necessary to ensure the confined dredged disposal areas, coastal restoration, and marsh creatio...

This paper presents the engineering properties of a lightweight-foamed glass aggregate (LWA-FG) for consideration as a lightweight fill material for use in retaining structure, embankment, highway, and bridge abutment construction in the United States. A laboratory study was conducted to evaluate the effect of compaction energy on the gradation, co...

Elevated temperatures in municipal solid waste landfills can pose health, environmental, and safety risks because they can generate excessive gases, liquids, pressures, and heat that can damage landfill infrastructure. This paper discusses mechanisms that can lead to elevated temperatures in the landfill and presents a case history to establish tre...

Due to concerns about post-construction stormwater runoff, Illinois Protection Environmental Agency (IEPA) plans to change its requirement for NPDES permits (ILR10 and ILR40). The objective of this research is to assist IDOT to identify performance and cost effective Post-Construction Best Management Practices (BMPs) to infiltrate and retain the fi...

On May 23, 2013, a truck-tractor with a flatbed semitrailer hauling an oversized container was traveling south on Interstate 5 (I-5) near Mount Vernon, Washington. While crossing the Skagit River, the oversized container struck portions of the through-truss bridge, which resulted in a 49-m (160-ft) simple-span section of the 339-m (1,112-ft) bridge...

This paper presents the equipment and Spectral Analysis of Surface Wave (SASW) approach for non-invasively characterizing railroad track ballast and foundation layers. Surface wave testing on a railroad track is more complicated than that on soil sites or pavements because of the presence of ballast, crossties, and rails as well as the complexity o...

This paper illustrates the impact of progressive settlement on a railway bridge transition using a three-dimensional dynamic numerical model that includes the train truck, rails, ties, ballast, subgrade, and bridge abutment and structure. A settlement law that relates tie load to ballast settlement is presented and demonstrated using an iterative f...

Ballast fouling is a problematic track condition that can lead to inadequate ballast performance. Prioritizing remediation of fouled ballast sites is difficult because no relationship between ballast fouling and track performance exists and fouled ballast performance depends on the amount, grain-size, type, plasticity, and moisture content of the f...

This paper presents two systems for non-invasively measuring transient rail and tie displacements using high-speed video cameras and accelerometers. The purpose of selecting these instruments is to develop a non-invasive instrumentation system that can monitor track performance under a range of environmental conditions. High-speed video cameras hav...

This paper presents a review of railroad track transition behavior, causes of undesirable transition performance, and designs that have exhibited desirable transition performance as determined by field measurements. The first focus of the paper is a review of common factors that lead to transition geometry deviations. These deviations involve the i...

The performance of four different municipal solid waste landfill liner systems common in the United States, that is, USEPA Subtitle D prescribed composite liner system, composite liner system consisting of a geomembrane (GM) overlying a geosynthetic clay liner (GCL), Wisconsin NR500 liner system, and a proposed four-component composite liner system...

This paper discusses two instrumentation techniques, linear variable differential transformers (LVDTs) and accelerometers, used to monitor and evaluate track structure behavior with the goal of nondestructively and quickly identifying track structural problems that eventually cause track geometry problems. LVDT results at a poorly performing bridge...

A common maintenance technique to correct track geometry at bridge transitions is hand tamping. This paper presents a non-invasive track monitoring system involving high-speed video cameras that evaluates the change in track behavior before and after hand or pneumatic tamping at a bridge transition zone experiencing reoccurring track geometry devia...

This paper compares the behavior of three different railway bridge transition zones to illustrate how poor tie support affects track performance. The three bridge transitions consist of a high-speed passenger line, a freight line, and a spur track. All bridge transitions were instrumented with accelerometers that allow tie support and track perform...

This paper presents a comparison of single- and multi-interface strength tests for a proposed landfill liner system configuration. The comparison includes peak and large displacement combination strength envelopes from single- and multi-interface direct shear tests for the same geosynthetic/geosynthetic, geosynthetic clay liner (GCL)/geomembrane, a...

Recent investigations of bridge transition zones experiencing reoccurring track geometry issues have exhibited unsupported ties along the approach near the bridge deck. These unsupported ties are identified as problematic as they can increase the loading of the ballast by mechanisms of impact loads and load redistribution. The development of unsupp...

A reoccurring maintenance issue for railroads in the United States is differential movement at bridge transitions and a common cause of this movement is the existence of gaps and load redistribution within the track system. These gaps can increase the applied loads in the track system with two examples being gaps between the rail and tie fastening...

This paper describes the use of Spectral Analysis of Surface Wave (SASW) for characterizing rail track ballast and foundation layers. Surface wave testing on a rail track is more complicated than on soil sites or pavements due to the presence of large ballast void spaces, crossties, and rails as well as the complex variation of shear-wave velocity...

Levee and floodwall seepage models based on two-dimensional (2D) conditions can underpredict landside vertical hydraulic gradients and uplift pressures due to excavations and convex bends. The Sherman Island levee system is used to calibrate a three-dimensional (3D) seepage model to evaluate the effect of finite landside excavations and convex leve...

The results of a Federal Railroad Administration research project into the factors that contribute to differential displacements at railroad track transitions are presented in this paper. Data from instrumented high-speed passenger (Amtrak) sites suggest that poorly supported ties increase the loads applied on the underlying ballast and can acceler...

This paper presents a review of railroad track transition designs that have performed well, e.g., ballasted bridge decks, hot-mixed asphalt (HMA) sublayer, and concrete wing walls parallel to the track, to guide future design and maintenance of bridge transitions instead of installing a concept and monitoring its performance. Using noninvasive moni...

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 rai...

Aluminum production wastes (APW) are produced during the recycling of aluminum scrap and dross. They are frequently disposed in dry form at Subtitle D nonhazardous waste landfills, where they may react adversely with liquids. Depending on the APW composition and landfill environment, the exothermic reaction can cause sustained temperature increases...

Shallow slides in levee and other embankment slopes are usually controlled by effective normal stresses less than 12 kPa (250 psf). For first-time slides in fine-grained soils, the fully softened shear strength is frequently used to model the strength of embankment soils because it represents the shear strength remaining after the effects of overco...

Most levee underseepage and uplift analyses are based on steady-state seepage and can yield conservative results. Although computations are simpler and steady-state seepage parameters are easier to determine and readily available, transient unsaturated seepage analyses are more representative of levee seepage conditions because boundary conditions...

This four-year project was extremely successful and well executed, even though a number of changed conditions developed during the project. Of these changed conditions, only one resulted in a claim that is discussed herein. This claim involved responsibility for repairing a failed 7-m-high embankment that was widened as part of the contract. This p...

This paper summarizes the appropriate equipment and test procedure for ballast shear strength testing using the direct shear method (ASTM D3080 and D5321) and presents some typical results. To accomplish this ballast testing, a full-scale direct shear box was developed that can accommodate an approximately 1 m (3 feet) wide and 0.6 m (2 feet) deep...