A Comparative Study on Methods of Estimating Liquefaction for Diyala Soil

The phenomenon of liquefaction is one of the most important problems in engineering projects.  It occurs in saturated sandy soils during the occurrence of earthquakes. Methods based on the standard penetration test (SPT) were developed to calculate the liquefaction potential according to the seismic loads. These methods have been developed and updated over time by some researchers. This paper analyses the comparison between methods of calculating liquefaction potential. The case study that was selected for the analysis of the comparison methods is Diyala Governorate soil. The methods that have been chosen for making a comparative analysis are the Japanese method, National Centre for Earthquake Engineering Research 1997 (NCEER) workshop, Task Force Report 2007 (Vancouver) and Boulanger and Idriss 2014. The analysis of results stated that the Boulanger and Idriss method is considered more suitable than others for calculating the potential for liquefaction in Diyala Governorate soil. It is found that the Boulanger and Idriss method has higher safety factor than the two methods (80.7% from Vancouver and 38.8% from the NCEER workshop) and less than the Japanese method