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Liquefaction Resistance of Geologically Aged Sand Deposits. David Saftner University of Minnesota Duluth. Outline. Liquefaction Overview Current Methods of Accounting for Age in Liquefaction Analysis Additional Data from Explosive Compaction Projects Griffin, Indiana
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Liquefaction Resistance of Geologically Aged Sand Deposits David Saftner University of Minnesota Duluth
Outline • Liquefaction Overview • Current Methods of Accounting for Age in Liquefaction Analysis • Additional Data from Explosive Compaction Projects • Griffin, Indiana • Comparison of Current Methods • Conclusions
“Simplified” Method • Whitman (1971) • Seed and Idriss (1971) • Updated several times since 1971
0.5 0.45 Robertson & Wride (1998) 0.4 Moss et al. (2006) Idriss & Boulanger (2008) 0.35 0.3 Cyclic Resistance Ratio, CRR 0.25 0.2 0.15 0.1 0.05 0 0 20 40 60 80 100 120 140 160 180 Normalized Tip Resistance, qc1N
Outline • Liquefaction Overview • Current Methods of Accounting for Age in Liquefaction Analysis • Additional Data from Explosive Compaction Projects • Griffin, Indiana • Comparison of Current Methods • Conclusions
Measured to Estimated Shear Wave Velocity Ratio (Hayati and Andrus, 2009)
Outline • Liquefaction Overview • Current Methods of Accounting for Age in Liquefaction Analysis • Additional Data from Explosive Compaction Projects • Griffin, Indiana • Comparison of Current Methods • Conclusions
CPT tip resistance, qc (MPa) 0 5 10 15 20 25 30 35 40 0 Pre-Blast Range (7 tests) One Week Range (6 tests) 2 4 6 8 Depth, z (m) 10 12 14 16 18 20
Outline • Liquefaction Overview • Current Methods of Accounting for Age in Liquefaction Analysis • Additional Data from Explosive Compaction Projects • Griffin, Indiana • Comparison of Current Methods • Conclusions
Griffin, IN Paleo-liquefaction sites North Blast site Photo courtesy of Mulzer Crushed Stone, Inc.
0 m Clay 2m 2 m 1m Upper Liquefiable Layer Loose ~GWT Sand 2m 4 m 6 m 5m 8 m Dense Sand 10 m Lower Liquefiable Layer Loose Gravelly Sand 12 m 4m 14 m
Tip resistance, qc (MPa) 6 8 10 12 14 16 18 10 10.5 Pre-Blast Mean (7 tests) One Week Mean (6 tests) 11 11.5 Depth, z (m) 12 12.5 13 13.5 14
Shear Wave Velocity, Vs (m/sec) 200 210 220 230 240 250 260 10 Pre-Blast V s 10.5 Post-Blast V s 11 11.5 Depth, z (m) 12 12.5 13 13.5 14
Explosive Compaction Projects in Aged Sand Deposits • Jebba Dam, Jebba, Nigeria • Douglas Lake, Michigan • Harriet’s Bluff, Georgia • Greeley, Colorado
Outline • Liquefaction Overview • Current Methods of Accounting for Age in Liquefaction Analysis • Additional Data from Explosive Compaction Projects • Griffin, Indiana • Comparison of Current Methods • Conclusions
Outline • Liquefaction Overview • Current Methods of Accounting for Age in Liquefaction Analysis • Additional Data from Explosive Compaction Projects • Griffin, Indiana • Comparison of Current Methods • Conclusions
Explosive compaction resets a deposit’s geotechnical age • Determine age using Andrus et al. (2009) MEVR approach • Strength gain factor using: