Assessment of Soil Liquefaction Safety Factors Under Different Earthquake Magnitudes

In the present study, seismic soil liquefaction in terms of factor of safety against liquefaction (FS) is evaluated by the IS Code: (Criteria for earthquake resistant design of structures. Bureau of Indian Standards, New Delhi [5]) (Part-I, 2016) for a site of IIT Patna campus. The FS values against liquefaction are evaluated under three different earthquake magnitudes, namely, M_w = 6.0, 6.5 and 7.0. A design peak ground acceleration of 0.24 g used as the Patna city lies in the Zone IV of the seismic zoning map of India as per IS code. In this paper, an evaluation of the severity of liquefaction in the form of liquefaction potential index (LPI) is also determined. The LPI is determined at a single borehole location from the obtained factors of safety (FS) to predict the potential of liquefaction to cause damage at the site of interest. The evaluated FS and LPI values from IS Code are compared with Idriss and Boulanger (Soil Dyn Earthq Eng 26:115–130 [4]) procedures to investigate the liquefaction behavior for cohesionless soils. The FS and LPI results of both SPT-based semi-empirical procedures indicate that the soil liquefaction probability increases during earthquakes with magnitude ≥7.0 at this site. It is also observed that the values of FS from IS code match with Idriss and Boulanger (Soil Dyn Earthq Eng 26:115–130 [4]) results under high earthquake magnitude.