| dc.description.abstract | This research examines the existing methods of evaluating soil liquefaction potential and seeks to develop new methods of evaluation. In the first part of the study, it verifies the traditional simplified methods for evaluating soil liquefaction and develops a new simplified method. In the second part of the study, a full probabilistic method of evaluating soil liquefaction is developed and applied to liquefaction risk analysis.
In total, there are 669 sets of SPT-N data, 388 sets of CPT-qc data, and 250 sets of shear wave velocity data on liquefaction and non- liquefaction case histories used in this research. Based on this data, a new simplified method for evaluating soil liquefaction called the “TAI method” is established that can use either SPT-N, CPT-qc or shear wave velocity data (Vs). Two indexes - the accuracy of prediction and the index of the at least error of safety factor - are used to verify the traditional simplified methods and compare them with the TAI method. The results show that the choice of the evaluation method used should be dependent on the type of data collected. The Seed method, NCEER method and TAI method work best for SPT data. The NCEER method, Juang method and TAI method are the best predictors for CPT data and the TAI method is the best choice for Vs data.
The traditional method for evaluating soil liquefaction assesses the liquefaction potential based on the safety factor it produces. However, criterion of safety factor adopted should depend on engineering’s experience. This study presents a reliability analysis method based on the popular Seed ’85 method and well known ＂first order, second moment＂ method. This method quantifies the variance of main factors affecting the result of soil liquefaction assessments from the liquefaction and non-liquefaction case histories. Next, a full probabilistic model of evaluating soil liquefaction is built by combining the reliability analysis of liquefaction method with earthquake hazard analysis. The model also takes into account the variance in the occurrences of earthquakes and the variance of soil resistance. Finally, monetary values are attached to the various outcomes of the model in order to establish a complete soil liquefaction risk analysis and decision making methodology. | en_US |