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Omaha, NE, United States

Douglas S.C.,Union Pacific Railroad | Wilson T.G.,Cdm Smith
2015 Joint Rail Conference, JRC 2015 | Year: 2015

Union Pacific Railroad's Moffat Tunnel Subdivision, west of Denver, Colorado, was significantly impacted by an approximately 500 to 1,000 year storm event that occurred between September 9, 2013 and September 13, 2013. As a result of this historic event, washouts, earth slides, and debris flows severely impacted track infrastructure by eroding track embankments, destabilizing surrounding native slopes, and overwhelming stormwater infrastructure. Emergency response activities performed to restore track operations at Milepost (MP) 25.65 and MP 22.86 required the integration of civil, hydraulic, environmental and geotechnical engineering disciplines into emergency response and construction management efforts. Additionally, support from UPRR's Real Estate Division was required when addressing private ownership and site access issues. The following text summarizes how coordinated efforts between various groups worked together in a pressure setting to restore rail service. The most significant damage occurred at MP 25.65 in a mountainous slot canyon between two tunnels accessible only by rail and consisted of a washout, approximately 200 feet (61 m) in length with a depth of 100 feet (30 m). MP 22.86 experienced slides on both sides of the track resulting in an unstable and near vertical track embankment which required significant fill and rock armoring. In addition to the embankment failures at MP 22.86, flood flows scoured around the underlying creek culvert, further threatening the geotechnical stability of the track embankment. The storm event highlighted the vulnerability of fill sections, where original construction used trestles. The repair plan engineered for MP 25.65 was developed to restore the lost embankment fill to near pre-flood conditions while limiting environmental impacts in order to minimize regulatory permitting requirements. Fill replacement performed during the initial emergency response was completed within 22 days, notwithstanding site remoteness and difficult access. Repair of the embankment required the placement of approximately 90,000 cubic yards (68,800 cubic meters) of fill and installation of four 48-inch (122-cm) culverts. Repair of embankment sloughing and scour damage at MP 22.86 was accomplished without the need for environmental permits by working from above the ordinary high water mark, using a "one track in-one track out" approach while restoring infrastructure to pre-flood conditions. A new headwall to address flow around the culvert inlet received expedited permit authorization from the U.S. Army Corps of Engineers by limiting the construction footprint through implementation of best management practices and minimizing placement of fill below the ordinary high water mark. Service interruptions, such as those at MP 22.86 and MP 25.65, require sound engineering practices that can be quickly and efficiently implemented during emergency response situations that often occur in less than ideal working environments. Track outages not only impact the efficiency of a railroad's operating network, but also impact interstate and global commerce as transportation of goods are hindered. The need to have a team of experienced engineering and construction professionals responding to natural disasters was demonstrated by this storm event. Copyright © 2015 by ASME.

Douglas S.C.,Union Pacific Railroad | Schaefer V.R.,Iowa State University
Geotechnical Special Publication | Year: 2015

Stone columns have been successfully used for transportation projects across the United States to treat clays, clayey sands, and silty sands for over three decades. However, stone column specific knowledge is generally accessible to only a select group of stone column experts and specialty contractors. Data mining identified numerous case histories that allowed both (1) lessons learned to be compiled from projects that encountered unsatisfactory performance and (2) current settlement estimating methods to be evaluated. The unsatisfactory performance revealed inadequacies in three broad aspects of every project: site investigation, design, and construction monitoring. Current methods of estimating settlements were evaluated with a case history and found the Priebe method to be preferred for routine settlement estimations. Numerical modeling confirmed that the change in stress resulting from the surface load in the layers underlying the stone column reinforced ground can be approximated using a traditional elastic, Boussinesq-type stress distribution. © ASCE 2015.

Salvati L.A.,1109 First Avenue | Guarente S.J.,234 E. Colorado Boulevard | Douglas S.C.,Union Pacific Railroad
Geotechnical Special Publication | Year: 2015

The 20-km (12.5-mi) Causeway was constructed in 1956-1959 to replace a wood trestle and maintain rail traffic across the Great Salt Lake. Most of the Causeway consists of rock fill founded on Glauber's Salt that is underlain by fine-grained lake sediments. To make the project economically feasible, Southern Pacific Railroad (then owner) accepted the risk of designing the Causeway to a factor of safety near 1.0, and Casagrande (1965) described the Causeway as an outstanding example of calculated risk. The original Causeway design considered that safety factors would improve with time as underlying fine-grained sediments gained strength. However, strength gain has not progressed as expected, and miles of the Causeway still have marginal factors of safety. This paper revisits the calculated risk, 55 years after construction, 30 years after a Haley & Aldrich investigation, and over 10 years after a failure along the Causeway. The results of a recent Jacobs Associates geotechnical investigation show that consolidation is not complete and the Glauber's Salt continues to be important in areas of marginal stability. The results have been used to assist the Union Pacific Railroad (now owner) in developing maintenance plans for the Causeway. © ASCE 2015.

Douglas S.C.,Union Pacific Railroad | Schaefer V.R.,Iowa State University
Proceedings of the Institution of Civil Engineers: Ground Improvement | Year: 2014

Many estimating methods have been developed for predicting the settlement of stone column reinforced ground. The Priebe method is the most common method used in practice. Even though the Priebe method does not capture all the parameters that affect the performance of stone column reinforced ground, the method is preferred due to its simplicity. An extensive literature search provided data to evaluate the Priebe method. The concept of reliability was incorporated to provide the framework for analysing the prediction method. The Priebe method was found to have an approximately 89% probability that the measured settlement will be smaller than the estimated settlement. The Priebe method was found not always to be conservative, with some possibility of settlement exceeding the estimated amount.

Mishra D.,University of Illinois at Urbana - Champaign | Kazmee H.,University of Illinois at Urbana - Champaign | Tutumluer E.,University of Illinois at Urbana - Champaign | Pforr J.,University of Illinois at Urbana - Champaign | And 2 more authors.
Transportation Research Record | Year: 2013

Characterizing railroad ballast behavior under repeated train loading is of significant importance for evaluating field settlement or permanent deformation potentials of unbound aggregate ballast layers. For the proper characterization of ballast behavior under dynamic loading, a new triaxial test setup was recently developed at the University of Illinois at Urbana-Champaign. Capable of accommodating cylindrical specimens with a diameter of 305 mm (12 in.) and a height of 610 mm (24 in.), this closed-loop servohydraulic test setup used a load cell and four displacement transducers mounted on the specimen to quantify deformation behavior under loading. Preliminary test results evaluating effects of different applied stress states as well as geogrid reinforcement on ballast behavior established the consistency and repeatability of this new test equipment. Laboratory findings are presented from an ongoing research study aimed at investigating the effects of different ballast types and field degradation trends on permanent deformation accumulation. The ballast type with the highest mill abrasion value was found to accumulate the highest permanent deformation under repeated load triaxial testing. Permanent deformation trends observed for four other ballast types showed direct correlations to the degrees of particle degradation observed in track sections constructed with these ballast materials and trafficked for approximately 18 months with a total track usage of 320 million gross tons.

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