Location

San Diego, California

Session Start Date

3-26-2001

Session End Date

3-31-2001

Abstract

Densification (Compaction) of loose saturated soils has been the most popular method of reducing earthquake related liquefaction potential. Compaction of a foundation soil can be economical when limited in extent, leading to a case of an “island” of improved ground (surrounded by unimproved ground). The behavior of the densified sand surrounded by liquefied loose sand during and following earthquakes is of great importance in order to design the compacted area rationally and optimize both safety and economy. This problem is studied herein by means of dynamic centrifuge model tests. The results of two heavily instrumented-dynamic centrifuge tests on glycerin-water saturated models of loose and dense sand, prepared adjacent to each other are discussed. Observed model response provided an improved understanding of dynamic liquefaction behavior of a densified ground surrounded by a loose liquefiable ground. The test results suggest the following concerns about “Islands” of densified soil: 1) there is a potential strength loss in the densified zone as a result of pore pressure increase due to migration of pore water (or fluid) into the island from the adjacent (loose) liquefied ground; 2) there is a potential for lateral deformation (sliding) within the densified island as the surrounding loose soil liquefies.

Department(s)

Civil, Architectural and Environmental Engineering

Appears In

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

Meeting Name

Fourth Conference

Publisher

University of Missouri--Rolla

Publication Date

3-26-2001

Document Version

Final Version

Rights

© 2001 University of Missouri--Rolla, All rights reserved.

Document Type

Article - Conference proceedings

File Type

text

Language

English

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Mar 26th, 12:00 AM Mar 31st, 12:00 AM

Seismic Response on Dense and Loose Sand Columns

San Diego, California

Densification (Compaction) of loose saturated soils has been the most popular method of reducing earthquake related liquefaction potential. Compaction of a foundation soil can be economical when limited in extent, leading to a case of an “island” of improved ground (surrounded by unimproved ground). The behavior of the densified sand surrounded by liquefied loose sand during and following earthquakes is of great importance in order to design the compacted area rationally and optimize both safety and economy. This problem is studied herein by means of dynamic centrifuge model tests. The results of two heavily instrumented-dynamic centrifuge tests on glycerin-water saturated models of loose and dense sand, prepared adjacent to each other are discussed. Observed model response provided an improved understanding of dynamic liquefaction behavior of a densified ground surrounded by a loose liquefiable ground. The test results suggest the following concerns about “Islands” of densified soil: 1) there is a potential strength loss in the densified zone as a result of pore pressure increase due to migration of pore water (or fluid) into the island from the adjacent (loose) liquefied ground; 2) there is a potential for lateral deformation (sliding) within the densified island as the surrounding loose soil liquefies.