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YOU WANT IT WHERE ?

YOU WANT IT WHERE ? DESIGN CHALLENGES ASSOCIATED WITH CONSTRUCTING THE NEW DOLWICK CONNECTOR INTO THE EXISTING I-275 EMBANKMENT. Presented by:. Craig Lee, P.E . Senior Engineer Lexington, Kentucky. HOW LOW-TECH AND HILLBILLY SENSE SOLVED.

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YOU WANT IT WHERE ?

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  1. YOU WANT IT WHERE? DESIGN CHALLENGES ASSOCIATED WITH CONSTRUCTING THE NEW DOLWICK CONNECTOR INTO THE EXISTING I-275 EMBANKMENT Presented by: Craig Lee, P.E. Senior Engineer Lexington, Kentucky

  2. HOW LOW-TECH AND HILLBILLY SENSE SOLVED DESIGN CHALLENGES ASSOCIATED WITH CONSTRUCTING THE NEW DOLWICK CONNECTOR INTO THE EXISTING I-275 EMBANKMENT Presented by: Craig Lee, P.E. Senior Engineer Lexington, Kentucky

  3. Cincinnati ProjectSite Louisville Lexington

  4. I-75 / I-71 I-275 Interchange Cincinnati / Northern Kentucky International Airport Ohio River Downtown Cincinnati

  5. Project Site Southbound I-75 / I-71 Westbound I-275

  6. Embankment Dry Creek Ramp from SB I-75 / I-71 to WB I-275

  7. Existing Slope Configuration Existing I-275 Ramp Existing Embankment: Limestone, Shale, & Clay  2 H 1 V  150 ft. Dry Creek Rock Line

  8. Design Task:Design a 2 lane road between Dry Creek and the existing I-275 Ramp without impacting either. Existing I-275 Ramp  150 ft. Dry Creek

  9. Proposed Slope Configuration Existing I-275 Ramp Right Side Tiedback Wall Dolwick Connector Left Side Tiedback Wall  150 ft. Dry Creek

  10. Geotechnical Design Team • Drilling & Sampling KY Transportation Cabinet Geotechnical Branch Horn & Associates • Laboratory Testing & Rock Core Logging KY Transportation Cabinet Geotechnical Branch • Geotechnical Analyses, Drafting, & Report S&ME, Inc.

  11. Drilling and Sampling Evaluation of Shear Strength Parameters Analyses Summary & Conclusions Presentation Overview

  12. Drilling & Sampling Program • Wall Borings Rock Cores Every 50 ft. Along Centerline of Walls SPT Sampling in Fill Material at Selected Locations Packer, Slope Inclinometers, Observation Wells • Anchor Borings Rock Cores & SPT Sampling Every 200 ft. Observation Wells

  13. Drill Access vs New Landslide

  14. Initial Approach:Minimize Disturbance to Existing Embankment

  15. Modified Approach:CarefullyCut Benches Into Slope

  16. Drilling Along Right Wall

  17. More Drilling Along Right Wall

  18. Reclaimed Slope

  19. Geology • Bull Fork Formation (2/3Limestone) • Bellevue Tongue of Grant Lake Limestone • (1/2 limestone) • Fairview Formation (1/3 limestone) • KopeFormation (1/5 limestone)

  20. Analysis Tasks • Evaluate Shear Strength Parameters • Assess Stability of Existing Slope • Calculate Wall Loads • Analyze Global Stability & Adjust Loads

  21. How to Evaluate Shear Strength Parameters ?

  22. How to Evaluate Shear Strength Parameters ? • Run Triaxial or Other Tests to Directly Measure Parameters ? • Rely on Correlations and Judgment ?

  23. The Great Debate • Some argued  was 14 to 19 degrees • Some argued  was closer to 30 degrees • Pretty Simple to Solve This Debate • Classify the Material then LCV and HCV

  24. Packer Permeability Testing • Performed in 4 Borings • k  6x10- 4 to 2x10- 3 cm/sec in Fill Material • k  10- 3 cm/sec ~ SW/SP • Conclusion: Fill is a “Tweener”

  25. Franklin Shale Rating System , c = f (SDI, PI)   12o - 17o c  120 - 170 psf FS = f ( , c, Slope Geometry )  0.7 - 0.8 Conclusion: Fill is a “Tweener” with Higher Shear Strength Parameters Model as “Hybrid” not “Pure Shale Embankment”

  26. What We Know • Numerous Failures in the Area • I-275 Embankment stable for years • The Geology of the adjacent Rock Cut • Typical Failure Surface Geometry

  27. Shear Strength Parameters Range of Parameters from Back - Analyses   24o - 28o c  100 - 300 psf Selected Design Parameters  = 24o c = 100 psf

  28. Target Factors of Safety Right Wall Local: 1.4 Global: 1.3 Left Wall Local: 1.4

  29. Calculation of Right Wall Loads Apparent Earth Pressure Method p = 0.65 ka H p = f (, , )  = assumed infinite backslope Kafrom Mueller-Breslau equation Limit Equilibrium Method Perform Local Slope Stability Analysis p = f (, , c, actual slope geometry)

  30. Right Wall Apparent Earth Pressure/ Limit Equilibrium Correlation

  31. Right Wall Design Load Equation Design Load = 2.47 x H2 x 

  32. Calculation of Left Wall Loads Local Stability Controls Right Wall Design Loads Global Stability Controls Left Wall Design Loads

  33. Right Wall Geotechnical Design Data Design Pressure ( Pd) Design Height ( Hd) Highest Allowable Pile Tip Elevation Allowable Passive Pressure ( Pp) Allowable End Bearing ( qa) Allowable Rock Socket Pressure ( Prs)

  34. Summary & Conclusions • Drilling & Sampling Program Provided Ample Data. • Characterization of the Embankment Required: • Observing and Believing Existing Conditions • Innovative Thinking • Lowest Conceivable Value – Highest Conceivable Value • Just Plain Engineering Judgment • Packer Permeability Testing was a Useful Component. • The Relationship Between Design Loads Computed by Apparent Earth Pressure and Limit Equilibrium Methods is Approximately 1:1 for Right Wall.

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