Variation in soil density of sand and peak ground acceleration to estimate liquefaction potential

Abstract Liquefaction is a phenomenon in which soil has no bearing capacity due to strong earthquakes. This research aims to assess the influence of variation in soil density of sand and peak ground acceleration on liquefaction potential risk. The value of N-SPT is used to represent sand density, and peak ground accelerations (PGA), from 0.1 g to 1.6 g, represent earthquake magnitude. The amplification factor of earthquake ground acceleration is based on the site class, SE to SC. The sand soil was modeled as one layer of soil having a thickness of 6 m and 30 m, with a density ranging from very loose sand to very dense sand. The results show that variation in soil thickness gives no significant difference in cyclic ratio tav’/sv’ for the same soil density, although a thicker soil 30 m gives a smaller cyclic ratio. Only soils (very loose sand to medium sand) with N-SPT values smaller than or equal to 16 have the potential to liquefy when subjected to PGA 0.1 g. All medium sands (N-SPT value 20 to 28) are potentially susceptible to liquefaction when subjected to PGA 1.0 g or higher (equal to magnitude Mw 9.1 or higher). However, dense sands are prone to liquefaction when subjected to any magnitude.