Optimization of Stabilization of Highway Embankment Slopes Using Driven Piles (Phase II \u2013 Development and Verification)

2015Final ReportPDFTech ReportCDOT-2015- 12271001291EmbankmentsPiles (Supports)Slope stabilitySoil stabilizationSlope steepnessDepth of failure surfacePile stiffnessDriven pilesUnited StatesColorado. Dept. of Transportation. Applied Research and Innovation BranchKiousis, Panos D.Griffiths, D.V.Gilchrist, TimColorado School of MinesColorado. Dept. of Transportation. Research BranchUnited States. Federal Highway AdministrationUS Transportation CollectionThis study examines the feasibility of using driven piles to stabilize highway embankment slopes. The literature review showed that there has been significant research done concerning the lateral capacity of piles. This research tends to be focused on different applications, but still shows that piles can add significant shear resistance to a slope. The outcome of phase I of this study established, that within limits, the driven piles can improve the stability of failing slopes. The original intent of this project, which was field validation of the findings of phase I was abandoned due to lack of funding. Instead, a parametric study was performed to examine the effects of slope steepness, depth of failure surface, and driven pile stiffness in the ability of driven piles to mitigate failing highway embankments due to weaknesses developed due to excess underground water during the snow melt periods. Based on the parametric study conducted here, it was concluded that driven piles have significant capacity to mitigate failing slopes of mountain highway embankments. Driven piles are more effective is failing slope mitigation when the slopes are less steep (3:1) irrespective of depth of failure. However, for steeper slopes (2:1), the ability of driven piles to provide efficient mitigation is limited only to shallow failures. It was also concluded that additional numerical studies are needed to examine the effects of varying material parameters, slope steepness, slope height, and failure surface depths. Finally a field validation is very important to establish whether the findings of computational studies can be used directly, or if calibration adjustments are needed. Implementation: Based on the results of the study it is recommended that the Colorado Department of Transportation pursue further computational studies along with a field validation study