A new technology for stabilizing slopes was developed by the Civil and Environmental Engineering Department at the University of Missouri-Columbia for the Missouri Department of Transportation. The technology uses Recycled Plastic Pins (RPPs) manufactured by pressure-molding recycled polyethylene with a compliment of sawdust and other by-products. The RPPs were manufactured by a Missouri firm. There are 20 to 30 other manufacturers in the United States. The constructability of the RPP technology was demonstrated by stabilizing two slides located in an embankment located on Interstate 70 at milepost 62 in Missouri. The embankment had a history of repeated slope failures, each of which was repaired by pushing the soil back in place. For this demonstration, the failed slopes were regraded to their original configuration and reinforced with a total of 317 pins (includes both slopes), or RPPs, installed on a 3-ft grid pattern using a mast-mounted vibratory hammer system. The RPPs were installed in November 1999. The RPPs were driven flush with the ground surface. The rate of installation of the pins averaged approximately 80 ft per hour. Instrumentation was installed on the RPPs and in the slope to monitor performance. Performance monitoring to date, June 2000, shows the slopes to be stable. A longer monitoring period is required before definitive conclusions on the performance can be made. The unit cost for installation of the RPP stabilization technology at the Emma, Missouri site was $3.90/sq ft - 25% less than for the traditional technique of using rock armor. The RPP technology offers an additional alternative for stabilization of shallow slope failures. Additional demonstrations and longer performance monitoring periods are warranted to document the range of applicability and validate the design methodology for the RPP stabilization technology.


  • English

Media Info

  • Features: Appendices; Figures; Photos; References; Tables;
  • Pagination: 82 p.

Subject/Index Terms

Filing Info

  • Accession Number: 00800255
  • Record Type: Publication
  • Report/Paper Numbers: RDT 00-007,, Final Report,, RI 98-007
  • Created Date: Oct 20 2000 12:00AM