Shear Wave Velocity Measurements During Ground Improvement at a Municipal Solid Waste Landfill Site in South Carolina

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Author: Clifford Astill castill@nsf.gov at NOTE Date: 5/5/98 12:15 PM Priority: Normal TO: acoles at nsf18 Subject: Abstract: CMS-9813564, Edward Kavazanjian, GeoSyntec Consult ------------------------------- Message Contents ------------------------------- Abstract: CMS-9813564, Edward Kavazanjian, GeoSyntec Consultants The objective of this project is to collect important data on the seismic response of municipal solid waste and on ground improvement to enhance liquefaction resistance through densification of sand by blasting. A unique opportunity exists to achieve these objectives simultaneously through shear wave velocity measurements during a blast-induced ground improvement pilot program at the Oakridge Sanitary Landfill in Dorchester County, South Carolina. Shear wave velocity in the solid waste is measured by monitoring ground motions induced by the test blasts, while shear wave velocity of the improved ground is measured before and after blasting using crosshole and downhole testing. These shear wave velocity measurements on the solid waste and in the ground before and after blasting will provide valuable insight into the dynamic behavior of these materials, and may identify important phenomenon that merit further investigation. Information on the shear wave velocity of municipal solid waste is limited to data obtained in southern California landfills, yet it is the basis for evaluation of the seismic response of landfills throughout the United States. Solid waste shear wave velocities at the relatively wet Oakridge Landfill that differ from those at arid southern California landfills would provide evidence of regional differences in waste properties. These potential differences could have a major impact on the seismic design of landfills outside of southern California. Recent data from a dynamic-consolidation ground-improvement project show that the induced densification was overestimated using conventional penetration testing due to increases in lateral stress. Shear wave velocity measurements before and after blasting can provide an important check on the validity of cone penetrometer resistance as a measure of improvement, and may provide a more immediate and cost-effective means of verifying improvement, and can provide important insights into the mechanisms of improvement. +=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+ Clifford J. Astill Ph:703-306-1362; X5083 Fax:703-306-0291 castill@nsf.gov www.eng.nsf.gov/cms/castill.htm Nat'l Science Fdn 4201 Wilson Blvd., Rm545 Arlington, VA 22230