Consistency Between Liquefaction Prediction Based on SPT, CPT, and Vs Measurements at the Same Sites
TEXAS UNIV AT AUSTIN
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Liquefaction induced ground failure is a major cause of damage during earthquakes. Liquefaction is a phenomenon that is not limited to one specific region in the world, but occurs worldwide. Liquefaction has not only caused major financial property loss but also has been attributed to the loss of lives throughout the world. Since the early 1970s, the prediction of liquefaction potential has been an area of high interest throughout the engineering community. The ability to predict whether or not a site in an active seismic zone will liquefy has the potential of saving a tremendous amount of money in property losses and more importantly the potential to save lives. This report uses the Vs data set compiled by Andrus, Stokoe, and Chung 1999 and presents SPT and CPT measurements from the same sites. In general, each site has experienced at least one earthquake, determination of field liquefaction has been made, at least one Vs measurement has been made in the critical layer, and at least one of the other field measurements, SPT or CPT, has been performed in the same critical layer. To begin, each type of measured field data is plotted with the presently accepted correlation for that particular technique and evaluated for accuracy. For sites that had at least two different measurements, a comparison of the methods is made. It is shown, for this particular data set, which current method was able to most accurately predict liquefaction. Changes to the currently accepted correlations, made to obtain better agreement between the different methods, are then discussed. Finally, correlations between the three different field measurement techniques are presented that is, Vsi - N1,60, Vsi - qc1,N, and qc1,N - N1,60 relationships are presented for the potentially liquefiable materials in this data set.