Development of an In Situ Dynamic Liquefaction Test
Rathje, EM
University of Texas, Austin, TX 78712

Chang, WJ
National Chi-Nan University, Chi-Nan, Taiwan

Stokoe II, KH
University of Texas, Austin, TX 78712

(Received 24 October 2003; accepted 16 June 2004)

Abstract
A new field-testing technique has been developed in which liquefaction and pore pressure generation characteristics of soil are measured in situ. The in situ dynamic liquefaction test utilizes a large, hydraulic shaker to load dynamically a soil deposit. The soil response is measured with embedded instrumentation. The embedded instrumentation includes newly developed liquefaction test sensors that incorporate velocity transducers (geophones) and pore pressure transducers in a single case. The recorded data are used to describe pore pressure generation and liquefaction characteristics in terms of the relationship between shear strain and induced pore pressure ratio. The analytical techniques used to compute shear strain from particle velocity measurements are discussed and compared. The results from testing a 1.2-m by 1.2-m by 1.2-m reconstituted field test specimen are presented. The shear strain—pore pressure relationships at selected numbers of loading cycles that were determined from the in situ dynamic liquefaction test are compared with those measured by other investigators in the laboratory. The field-measured relationships show the same shape as the lab-measured relationships, but the field data indicate a smaller threshold strain for pore pressure generation (~0.005 %). This difference is attributed to the low effective stresses in the reconstituted field specimen.

Keywords:
field testing, liquefaction, pore pressure shear strain

Paper ID: GTJ12289
DOI: 10.1520/GTJ12289

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Author Rathje, EM Affiliation University of Texas, Austin, TX 78712 Author Chang, WJ Affiliation National Chi-Nan University, Chi-Nan, Taiwan Author Stokoe II, KH Affiliation University of Texas, Austin, TX 78712 Author Rathje EM, Chang WJ, Stokoe II KH Title Development of an In Situ Dynamic Liquefaction Test Symposium , Committee on