Liquefaction of sub-soil is a phenomenon in which partially saturated or saturated loose cohesionless sub-soil, especially loose fine sand, significantly lose their strength and stiffness in response to applied stresses. It occurs generally during earthquake shakings because of the generation of surplus pore water pressure, causing it to lose its effective stress and act like a liquid. Essentially, prediction of the liquefaction severity accurately is very important for liquefaction-prone sites for different seismic conditions. All the structures that are constructed on sub-soil are susceptible to liquefaction and can get damaged as a result of earthquake ground motion. Since earthquakes are one of the most disastrous events, analysis for sub-soil needs to be conducted to understand the soil behavior and its stability against liquefaction at different sites. There are several simplified techniques to assess liquefaction potential on the basis of standard penetration test (SPT), cone penetration test (CPT), and shear wave velocity (Vs) test. In this paper, simplified liquefaction analysis has been carried out based on SPT data for 10 sites in Bahraich District situated in Uttar Pradesh. Liquefaction potential index (LPI) has been calculated and the level of liquefaction severity is classified. It was observed that out of 10 site that have been evaluated 5 had moderate to high severity; while, the remaining 5 sites had high to very high severity. The classification helped in preliminary comprehension of the liquefaction susceptibility of the sites selected for construction.

Liquefaction has been known as a phenomenon in which the shear strength and stiffness of saturated soil are reduced by the generation of pore water pressure under earthquake loading. Consequently, liquefaction-induced settlement can result in severe damage including building cracks or slope failure, which pose a threat to human lives and properties. In the current Vietnamese standard TCVN 9386:2012, liquefaction potential hazard is often evaluated using the simplified method, which solely identifies the areas with a high risk of liquefaction. Prediction of Safety Factor (FS), Settlement (S), Liquefaction Potential Index (LPI), and Liquefaction Severity Number (LSN) has not received sufficient attention to a completeness standard. This study assesses the liquefaction of the site at Ho Chi Minh City, Vietnam by using four conventional methods: the simplified procedure, linear equivalent analysis, loosely-coupled effective stress analysis, and fully-coupled effective stress analysis based on standard penetration test (SPT) data in Ho Chi Minh Metropolitan City. A class of seismic events that are compatible with the design response spectrum in the Vietnamese standard TCVN 9386:2012 is used as input ground motion at the bedrock. According to the results of different methods, maps of ground settlement, LPI, and LSN are proposed as useful references for construction works on such soils, which may have a high potential for liquefaction and subsidence.