PHASE II - EMBANKMENT WIDENING AND GRADE RAISING ON SOFT FOUNDATION SOILS. FINAL REPORT

The finite element technique using a cap elastic-plastic work-hardening soil behavior model was applied to the analysis of embankments constructed on soft foundation soils. A procedure was provided to estimate the cap model parameters from conventional field and laboratory test results. A sensitivity analysis of the cap model parameters comparing the observed and calculated responses was also provided. Results indicate that the undrained shear strength and over-consolidation ratios were observed to have the most-significant influence on the predicted model behavior. The technique was then applied to the analysis of two examples. The examples were based on actual highway projects in Indiana where information on these projects was provided by Indiana Department of Transportation personnel. Results of the analysis were used to determine the influence of several factors on reinforced and unreinforced embankment behavior. The results indicated that the crust strength and foundation compressibility had the most-significant influence on embankment fill and foundation soil behavior and the potential benefit possible with reinforcement. Reinforcement type/modulus also influenced the behavior of the embankment fill and foundation soil but to a lesser extent when compared to crust strength. The use of reinforcement for widening and grade raising of existing embankments appeared to be beneficial in reducing lateral movement.