68th Canadian Geotechnical Conference and 7th Canadian Permafrost Conference

LIQUEFACTION MITIGATION USING RAPID IMPACT COMPACTION AND A COMPARISON OF SPT AND CPT CONFIRMATION TESTING

Session: Problematic Soils and Ground Improvement I / Sols problématiques et amélioration du comportement I

Jason Brown, GeoSolv Design/Build Inc. (Canada)
Nicolas LeBlanc, Golder Associates Ltd. (Canada)
Serge Bourque, Houle Chevrier Engineering Ltd. (Canada)
Mark Tigchelaar, GeoSolv Design/Build Inc. (Canada)

The East Quadrant Water Distribution System in Kemptville, Ontario was expanded in 2014 to include a new pump station and at-grade water silo. The geotechnical investigation for the expansion identified a 2.3 m to 3.4 m thick layer of potentially liquefiable sand. Rapid Impact Compaction (RIC) was specified to densify the sand layer, thereby increasing the factor of safety against liquefaction to be confirmed using Standard Penetration Testing (SPT). After completing the SPT confirmatory testing, the resulting SPT N60 values were found to have a wide range of results. Cone Penetration Testing (CPT) was carried out to supplement the SPT results. This paper discusses the use of RIC to densify the sand layer within a 5 m radius of the new structures and compares the results of both the SPT and CPT confirmatory testing.