University of Wisconsin-Madison. Railway Substructure Stabilization with Polyurethane Injections

Transcription

1 UW Madison Geological and Geotechnical Engineering Geological Engineering Transporta1on Geotechnics Civil & Environmental Engineering University of Wisconsin-Madison Railway Substructure Stabilization with Polyurethane Injections Andrew Keene, Jim Tinjum, Tuncer Edil, and Randy Brown University of Wisconsin- Madison Slide 1

2 Background Problem Motivation Outline Materials Rigid-Polyurethane Foam (RPF) Polyurethane-Stabilized Ballast (PSB) Methods for Mechanical Property Evaluation Plastic deformational behavior Compressive and flexural properties Feasibility of Strategically Placed Polyurethane Layer in Track-Substructure Evaluate track mechanical behavior after stabilization University of Wisconsin- Madison Slide 2

3 Background: Railway Track Components Problem: Ballast layer deteriorates under numerous loading repetitions Deterioration in the substructure leads to permanent deformation in the track, threatening rail operations Objective: Prevent track deformation while enhancing rail operations Mid- Con(nent Research Forum 2012 University of Wisconsin- Madison September 6 Keene, Edil, Tinjum, & Brown Slide 3

4 Motivation: Track Maintenance Costs Maintenance of ballast is $500M/ year For 150,000 km of Class 1 freight rail in the US, (Chrismer and Davis 2000) Fouling Level Increases During Service Life of Track University of Wisconsin- Madison Slide 4

5 Types of Fouling Non- Cohesive Fouling (i.e., between P4 & P200) Cohesive Fouling (i.e., P200) Coal Fouling Mineral Fouling Clay Fouling (Ebrahimi et al. 2010) P4 = 4.75 mm; P200 = mm University of Wisconsin- Madison Slide 5

6 UW-Madison Railroad Research Mitigating Ballast Fouling Impact and Enhancing Rail Freight Capacity Prevent ballast layer deterioration and track deformation Enhance railway track capacity and maintained capabilities Polyurethane reinforcement of ballast layer is proposed Dr. Randy Brown Andrew Keene Steve Reed Ben Warren University of Wisconsin- Madison Slide 6

7 Materials: Uretek USA Inc. Polyurethane Rigid-Polyurethane Foam (RPF) Polyurethane-Stabilized Ballast (PSB) Uretek Polyurethane: Rigid-Polyurethane Foam High density, expanding, thermoset, resin system Reaches 90% of full compressive and tensile strength in 15 minutes Research Involves Use of Technology With Rail Ballast Mid- Con(nent Research Forum 2012 University of Wisconsin- Madison September 6 Keene, Edil, Tinjum, & Brown Slide 7

8 Methods: Large-Scale Cyclic Triaxial (LSCT) Cyclic loading machine to simulate railway traffic Equivalent to: Deviator Stress, σ = 300 kpa Confining Stress, σ = 90 kpa (Ebrahimi 2011) Axle load: 20, 30, and 40 tons Automated data acquisition system (LabView) 600-mm 300-mm University of Wisconsin- Madison Slide 8

9 Unconfined Compressive Strength Testing L = 0.4 m Flexural Beam Testing L = 0.76 m Mid- Con(nent Research Forum 2012 University of Wisconsin- Madison September 6 Keene, Edil, Tinjum, & Brown Slide 9

10 Results: Stabilized and Un-stabilized Cumulative Plastic Strain, ε P (%) Tested over 200,000 loading repetitions in cyclic triaxial compression Fouled Ballast, FI 5% & MC 15% Clean Ballast PS-Clean Ballast PS-Fouled Ballast, FI 25% & MC 15% PS-Recycled Ballast, P25.4 mm & R19 mm Clean Ballast Reference Line 0 P4 = 4.75 mm P200 = mm Deviator Stress, σ d (kpa) PS = Polyurethane Stabilized MC = % Moisture Content FI = Fouling Index (%)= P4+P200 University of Wisconsin- Madison Slide 10

11 PSB and Constituent Mechanical Properties 7, Mechanical Strengths (kpa) 6,000 5,000 4,000 3,000 2,000 1,000 0 ρ RPF = 200 kg/m 3 ρ b = 1,580 kg/m 3 Elastic Moduli (MPa) Compressive Flexural Tensile Compressive Flexural Tensile Compressive Flexural Tensile Compressive Flexural Tensile Compressive Flexural Tensile Compressive Flexural Tensile PSB RPF Ballast RPF = Rigid Polyurethane Foam PSB RPF Ballast University of Wisconsin- Madison Slide 11

12 Material Property Summary Mechanical Properties PSB plastic deformational behavior far less than clean ballast, recycled ballast, and fouled ballast PSB elastic moduli typically less than ballast Further Considerations and Restated Questions: Effect of lower modulus on overall track response? Fatigue lifecycle for PSB layers? Next Step: Modeling PSB in Track-Substructure University of Wisconsin- Madison Slide 12

13 PSB Model Percolation-Injection Concept: Model percolationinjection method for PSB stabilization Goal: Determine track elastic response Result: Areas of lower modulus did not have negative impact RPF = Rigid Polyurethane Foam University of Wisconsin- Madison Slide 13

14 PSB Model Subsurface-Injection 3D View Longitudinal View Concept: Model subsurface-injection method for PSB trackbeds Goal: Determine strain at base of layer for input into analytical fatigue model Result: Strain measured would give PSB fatigue lifecycle at MGT Lateral View PSB Trackbed Layer (Rose & Konduri 2006) ε t = Flexural Strain RPF = Rigid Polyurethane Foam University of Wisconsin- Madison Slide 14

15 Conclusions Mechanical Properties PSB outperforms other track-substructure materials PSB had typically higher elastic deformational behavior Feasibility of Stabilization in Track-Substructure Stabilization does not have negative impact on elastic response Injection methods are feasible for track stabilization PSB can greatly increase track mechanistic lifecycle University of Wisconsin- Madison Slide 15

16 Future Work Ballast Stabilization with Polyurethane: Evaluation of polyurethane-stabilized ballast with varying levels of fouling and water content Use of method in field-scale tests or track maintenance operations Warning System and Inspection Project: Correlate fouling conditions found using GPR and TDR with track deformation measure with FOS Select track segment for case study evaluation of inspection methods University of Wisconsin-Madison Rail Research: Incorporate results from Mechanistic and non-destructive evaluation research into test track or field application Continue to advance geotechnical approaches for enhancing track inspection techniques, maintenance prediction, and sustainability using mechanistic-based research Evaluate impacts of frac sand loads on new and existing Wisconsin rail infrastructure University of Wisconsin- Madison Slide 16

17 Questions? Acknowledgements References Center for Freight Infrastructure Research and Education (CFIRE) Uretek USA Inc. UW-Madison Laboratory Staff: William Lang Xiaodong Buff Wang Special Thanks To: Dr. Ali Ebrahimi Gizem Bozkurt ASTM Standards, Annual Book of ASTM Standards, ASTM International, West Conshohocken, PA Ebrahimi, A. (2011). Deformational Behavior of Fouled Railway Ballast. PhD thesis, Department of Civil and Environmental Engineering, University of Wisconsin, Madison. Ebrahimi, A. and Keene, A.K. Maintenance Planning of Railway Ballast, In proceedings of the AREMA 2011 Annual Conference, Minneapolis, Minnesota, September Keene, A. (2012). Mitigating ballast fouling and enhancing rail-freight capacity. MS thesis, Dept. of Civil and Env. Eng., University of Wisconsin- Madison. Rose, J.G. & Konduri, K.G. (2006). "KENTRACK A Railway Trackbed Structural Design Program." AREMA 2006 Annual Conference, Louisville, Kentucky, September Zhipeng Su Ben Warren University of Wisconsin- Madison Slide 17