Remediation of a Failing MSE Wall by Jet Grouting

Mechanically Stabilized Earth (MSE) walls retain abutment and side-hill fills for the 3-span bridge that takes State Route (SR) 87 over Whiskey Springs in Sunflower located between Phoenix and Payson in Arizona. In May 2001, approximately one year after construction, the 13.7m (45 ft) high MSE wall and the west wing wall at the south abutment started showing distress. Emergency geotechnical investigations were performed by the Arizona Department of Transportation (ADOT) in June 2001. It was determined that the wall was experiencing failure with respect to global stability as well as bearing capacity. Several mitigation measures were evaluated. Two grouting procedures, jet grouting and soil fracture, were put out to bid. The jet grouting technique was used by the selected contractor and the wall was stabilized. The investigation, design and remediation process as well as results of instrumentation monitoring of the wall are presented in this paper.