APPLICATION OF KRIGING ESTIMATION METHODS IN SITE LIQUEFACTION POTENTIAL ASSESSMENT

Liquefaction assessment is an important prerequisite for implementing liquefaction mitigation measures. Kriging theory in geostatistics is an effective tool for spatial interpolation of parameters,which mainly includes ordinary Kriging(OK),simple Kriging(SK) and indicator Kriging(IK). A liquefiable site in a coastal industrial park in Taiwan,China was adopted as a case study. The liquefaction potential index(LPI)as well as liquefaction probability(PL)were used to describe the degree of liquefaction. The effectiveness of three Kriging estimation methods,IK_LPI,OK_LPI and OK_PL methods,on the liquefaction assessment were explored. The results show that under the 1999 Chi-Chi earthquake,the liquefaction maps of estimated mean value by the three methods are different. The liquefaction maps are affected by the evaluation index as well as the mapping method,and the former factor has a greater impact. It is found from the liquefaction maps of estimated variance that the variance increases consistently with the increase of distance to the test data. By comparing the results of three evaluation methods with the liquefaction observations,the OK_LPI and OK_PL methods are consistent with the field observations,indicating a reliable evaluation. The cross validation results show that the prediction errors of the three methods are small,and they can well reflect the variation trend of the test data. Overall, the OK_LPI method is recommended to evaluate the liquefaction potential of the site.