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Top1. Introduction
Liquefaction is an exciting topic and active area of research in geotechnical earthquake engineering, although it is quite complex phenomena to be fully understood. The topic initially gained attention following the widespread damage due to liquefaction as a result of Alaska (1964) and Niigata earthquakes (Fukuoka, 1966; Seed, 1968). During liquefaction, soil experiences an increased deformation due to the reduction in effective confining stress when there is a build-up of high excess pore water pressure. Liquefaction generally occurs only in saturated clean sand. Fine grained soils do not generally liquefy (Krammer, 1996). Cohesionless soil deposit sometimes contains significant fine contents and some field observations also exhibit the liquefaction occurrence in sandy-silt/silty-sand type of soils after earthquake event (Ishihara et al., 1980; Boulanger et al., 1999; Orense et al., 2011; Cox et al., 2013). Since then, the study on the liquefaction characteristics of sandy-silt/ silty-sand type of soils has received much attention.
Several methods of liquefaction potential evaluation are available and these methods mainly utilize different geotechnical data from field tests (Seed and Idriss, 1971; Youd et al., 2001; Idriss and Boulanger, 2006). In-situ shear wave velocity serves an alternative to penetration test in the liquefaction susceptibility evaluation (Andrus and Stokoe, 2000; Youd et al., 2001; Andrus et al., 2004). In order to study the liquefaction susceptibility of soil under controlled conditions in the laboratory, cyclic triaxial apparatus is used worldwide. It can be used to study the influence of different parameters on liquefaction susceptibility (Chien et al., 2000; Arab et al., 2002; Xenaki V.C. and Athanasopoulos G.A, 2003; Ravishankar et al. 2005; Paul et al., 2007; Stamatopoulos, 2010; Kumar et al., 2014; Kumar et al., 2020). Effect of presence of different percentage of silt content in sandy soils has also been studied by several researchers in laboratory using cyclic triaxial (Polito and Martin, 2001; Xenaki and Athanasopoulos, 2003; Stamatopoulos, 2010; Karim and Alam, 2014; Wei and Yang, 2019). Uniform clean sand deposits are quite hard to find as very often this deposit exists with certain percentage of silt content. Now as the behavior of a soil deposit under cyclic loading may significantly vary for different types of soil deposit depending on the nature, so, each of them needs to be characterized for cyclic loading in the laboratory under controlled condition.