STM Journals Peer-reviewed research from Consortium e-Learning Network

Journal of Geotechnical Engineering

Soil liquefaction vulnerability assessment of Sylhet city based on SPT value

  1. Abujar Gifari
  2. Mushtaq Ahmed
  3. Shriful Islam
  4. Md Mohaiminul Hassan Sojib

Abstract

Bangladesh is an earthquake-prone country due to its geographic location. Sylhet, a divisional city, is situated in Zone IV, the most seismically active area in the country, according to the Bangladesh National Building Code (BNBC). A major earthquake can cause devastating effects in the subsurface, such as liquefaction, landslides resulting from a reduction of soil shear resistance. In this study, liquefaction potentiality of soil in Ward No. 9 of Sylhet City Corporation has been analyzed using soil parameters, especially the Standard Penetration Test (SPT) data. For the present study, two hundred borehole data from 67 locations with different drilling depths up to 19.5 m each were analyzed. The Simplified Procedure was used to calculate the factor of safety against liquefaction and to estimate the liquefaction potential index (LPI). A modeling approach, areal interpolation has been introduced to evaluate the liquefaction potential for the entire ward using ArcGIS 10.8. The study shows that about 84% of sample locations have an LPI value greater than 15, indicating the zone is severe liquefaction-prone. A contour map of the LPI has been prepared for Ward No. 9 for vulnerability assessment. This study also evaluates the allowable capacity of bored piles in some critical borehole locations considering liquefaction of the soil and finds a substantial loss of bearing capacity.

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