Energy-Based Evaluation and Remediation of Liquefiable Soils

Abstract

The state-of-practice for performing remedial ground densification and evaluating earthquake liquefaction potential of loose saturated sands have evolved relatively independent of each other. This is in spite of the fact that the induction of liquefaction is typically requisite for remedial ground densification of sands. Simple calculations are presented herein for estimating the mechanical energy required to densify a unit volume of clean, loose sand using deep dynamic compaction, vibro-compaction, and explosive compaction. These computer energies are compared with that required to induce liquefaction during an earthquake using the Green-Mitchell energy based liquefaction evaluation procedure. The comparison highlights the importance of the efficiency of the method in which the energy is imparted to the soil and the importance of the mode of dissipation of the imparted energy (e.g., possible modes of energy dissipation/expenditure include: breaking down of initial soil structure, ramming soil particles into denser packing, and radiating away from the treatment zone). Additionally, the comparison lays the preliminary groundwork for incorporating the vast knowledge base gained from fundamental studies on earthquake induced liquefaction into the design procedures of remedial ground densification techniques.