Location

San Diego, California

Session Start Date

5-24-2010

Session End Date

5-29-2010

Abstract

This paper presents two case histories of ground improvement by dynamic compaction (DC) at the Myra Falls mine in Vancouver Island, British Columbia, Canada. Dynamic compaction was employed to densify soils at two sites within the operating mine: a waste rock dump beneath a new processing plant to reduce settlements beneath the structure foundations (Site A); and coarse fluvial and colluvial soils at the toe of an existing tailings embankment to improve seismic resistance against liquefaction (Site B). At Site A, the variable plant loadings required variable compaction energy to achieve uniform foundation performance. At Site B, the foundation soils contained some fine grained soils that dictated a time-controlled sequential DC approach to allow excess pore pressures to dissipate between passes. Because of large uncertainties in the expected performance of DC at both sites, a fair and cost effective DC contract based on unit price per energy was adopted, instead of the traditional performance-based lump sum price contract. This paper describes the ground conditions at the two sites, DC methodologies employed, and ground improvement performance based on measurements of crater volumes and pre- and post-densification in-situ testing by Becker Penetration Tests.

Department(s)

Civil, Architectural and Environmental Engineering

Appears In

International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics

Meeting Name

Fifth Conference

Publisher

Missouri University of Science and Technology

Publication Date

5-24-2010

Document Version

Final Version

Rights

© 2010 Missouri University of Science and Technology, All rights reserved.

Document Type

Article - Conference proceedings

File Type

text

Language

English

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May 24th, 12:00 AM May 29th, 12:00 AM

Ground Improvement by Dynamic Compaction at a Tailings Disposal Facility

San Diego, California

This paper presents two case histories of ground improvement by dynamic compaction (DC) at the Myra Falls mine in Vancouver Island, British Columbia, Canada. Dynamic compaction was employed to densify soils at two sites within the operating mine: a waste rock dump beneath a new processing plant to reduce settlements beneath the structure foundations (Site A); and coarse fluvial and colluvial soils at the toe of an existing tailings embankment to improve seismic resistance against liquefaction (Site B). At Site A, the variable plant loadings required variable compaction energy to achieve uniform foundation performance. At Site B, the foundation soils contained some fine grained soils that dictated a time-controlled sequential DC approach to allow excess pore pressures to dissipate between passes. Because of large uncertainties in the expected performance of DC at both sites, a fair and cost effective DC contract based on unit price per energy was adopted, instead of the traditional performance-based lump sum price contract. This paper describes the ground conditions at the two sites, DC methodologies employed, and ground improvement performance based on measurements of crater volumes and pre- and post-densification in-situ testing by Becker Penetration Tests.