TITLE:
Liquefaction Potential Assessment of Guwahati City Using One Dimensional Ground Response Analysis
AUTHORS:
Amar Farooq Siddique, Binu Sharma
KEYWORDS:
Ground Response Analysis, Equivalent Linear Method, Non Linear Method, Soil Liquefaction
JOURNAL NAME:
Journal of Geoscience and Environment Protection,
Vol.8 No.5,
May
21,
2020
ABSTRACT: Guwahati
city which lies in the North Eastern region of India, falls in the highest seismic risk zonal level i.e. zone
V in India. However,
there are very few works on seismic hazard analysis of Guwahati soil considering
the local site effects. The effect of large modifications
in seismic waves that occur due to variation in soil properties near the surface
of the earth is of great importance in geotechnical earthquake engineering. Seismic
soil liquefaction, a soil seismic hazard, is evaluated
in Guwahati city in terms of factor of safety against liquefaction along
the soil profiles using ground response analysis. One dimensional ground response analysis has been conducted using equivalent
linear and non linear method using the Deepsoil software. The input motion of 2011
Sikkim earthquake (Mw = 6.9) having bedrock PGA of 0.152 g at 30 m depth
is considered. A comparative study has been made of the equivalent linear and non
linear analysis in terms of surface PGA (g), maximum strain (%), maximum stress
ratio and liquefaction potential using soil profiles of Guwahati city. It has been
observed that stiffer soil layer results in similar PGA from both the analysis however
non linear analysis generally gives a lesser
surface PGA than by equivalent linear analysis. Non linear analysis generally
gives a higher strain range and a lower maximum stress ratio as compared to the
equivalent linear method. A slightly higher factor of safety is obtained using non
linear analysis than using equivalent linear analysis. A soil database of 200 bore
holes was used for the study. Spatial distribution of soil liquefaction potential is
presented in the form of GIS based maps of factor of safety values.