Location

San Diego, California

Session Start Date

5-24-2010

Session End Date

5-29-2010

Abstract

The objective of the study presented herein is to compare the energy required to densify loose, liquefiable sand by various techniques and the energy required to liquefy the soil by earthquake shaking. The states-of-practice for performing remedial ground densification and evaluating earthquake liquefaction potential of loose saturated sands have evolved relatively independently of each other. This is in spite of the fact that the inducement of liquefaction is typically requisite for remedial ground densification of sands. Using the energy required to induce liquefaction as a common metric, simple calculations are presented for estimating the mechanical energy required to densify a unit volume of clean, loose, saturated sand using deep dynamic compaction, vibrocompaction, and explosive compaction. These computed energies are compared with that required to induce liquefaction during an earthquake per the Green- Mitchell energy based liquefaction evaluation procedure. The comparison highlights the importance of the efficiency of the process by which the energy is imparted to the soil and the importance of the mode of dissipation of the imparted energy (e.g., breaking down of initial soil structure, ramming soil particles into denser packing, and/or radiating away from the treatment zone). Additionally, the comparison lays the groundwork for incorporating the vast knowledge from fundamental studies on earthquake induced liquefaction into design procedures for remedial ground densification.

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

Comparison of Energies Required to Densify Liquefiable Soil

San Diego, California

The objective of the study presented herein is to compare the energy required to densify loose, liquefiable sand by various techniques and the energy required to liquefy the soil by earthquake shaking. The states-of-practice for performing remedial ground densification and evaluating earthquake liquefaction potential of loose saturated sands have evolved relatively independently of each other. This is in spite of the fact that the inducement of liquefaction is typically requisite for remedial ground densification of sands. Using the energy required to induce liquefaction as a common metric, simple calculations are presented for estimating the mechanical energy required to densify a unit volume of clean, loose, saturated sand using deep dynamic compaction, vibrocompaction, and explosive compaction. These computed energies are compared with that required to induce liquefaction during an earthquake per the Green- Mitchell energy based liquefaction evaluation procedure. The comparison highlights the importance of the efficiency of the process by which the energy is imparted to the soil and the importance of the mode of dissipation of the imparted energy (e.g., breaking down of initial soil structure, ramming soil particles into denser packing, and/or radiating away from the treatment zone). Additionally, the comparison lays the groundwork for incorporating the vast knowledge from fundamental studies on earthquake induced liquefaction into design procedures for remedial ground densification.