Date of Award

12-2010

Document Type

Thesis

Degree Name

Master of Science (MS)

Legacy Department

Civil Engineering

Advisor

Andrus, Ronald D

Committee Member

Juang , C. Hsein

Committee Member

Ravichandran , N. (Ravi)

Abstract

Empirical relationships for correcting liquefaction resistance of partially saturated soil using longitudinal (P-) wave velocity (VP) and shear (S-) wave velocity (VS) are developed and evaluated in this thesis. The relationships are based on the laboratory test results for four different types of sands and one silt published by other investigators. The data used to develop the relationship with VP exhibit less scatter than the data used to develop the relationship with VP/VS. For this reason, the VP based relationship is recommended for correcting liquefaction resistance of partially saturated soil.
Analyzing liquefaction case history data from different earthquake sites in the United States, Japan and Taiwan, it is found that the critical layer at about 80% of the case history sites have average VP equal to or greater than 1,400 m/s. Thus, no correction is necessary for soils with VP &ge 1400 m/s as they are saturated for practical purposes. Liquefaction resistances for eight case histories with VP < 1,200 m/s are corrected and plotted on the VS-based CRR chart by Andrus and Stokoe (2000). Significant improvements are observed in the predictions for three cases of no liquefaction that plot in the liquefaction predicted region before the partial saturation correction.
The soil zones below the groundwater table at six geotechnical investigation sites in the South Carolina Coastal Plain are characterized using VP data obtained from seismic crosshole tests. Partially saturated soil layers with thicknesses of 0.3 to 1.3 m were found immediately below the groundwater table at four of the six sites.

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