DOI: 10.4018/IJGEE.2020010101
International Journal of Geotechnical Earthquake Engineering
Volume 11 • Issue 1 • January-June 2020
Copyright © 2020, IGI Global. Copying or distributing in print or electronic forms without written permission of IGI Global is prohibited.
1
Evaluation of Liquefaction Potential
of Soil at a Power Plant Site in
Chittagong, Bangladesh
Soumyadeep Sengupta, Vellore Institute of Technology, Vellore, India
Sreevalsa Kolathayar, National Institute of Technology Karnataka, Mangaluru, India
ABSTRACT
This study presents an evaluation of liquefaction potential for combined cycle power plant site located
in the Chittagong district, Bangladesh, using standard penetration test blow counts (SPT-N values).
The peak ground acceleration (PGA) values at a bedrock level were estimated deterministically using
both linear and point source models as well as different ground motion prediction equations (GMPEs).
The surface level hazard was estimated using amplification factors for the soil conditions present
and the response spectrum at the center of the plant site was plotted. The liquefaction potential for
the site was arrived at by using the SPT-N values of 33 boreholes in the site and at every 3-meter
interval from the ground level to a depth of 30 meters. The results from the LPI contours at successive
depths indicate that in the majority of the borehole locations, the soil up to 15 meters depth had a
significant hazard of liquefaction. These findings from the present study can prove to be crucial from
the structural point of view, for any future construction activities in the area.
KEywoRdS
Liquefaction, LPI, Peak Ground Acceleration, Site Class, SPT
INTRodUCTIoN
Evaluation of liquefaction resistance of soils is of utmost importance when it comes to important sites
like power plants due to the presence of critical structures. Soil Liquefaction resistance has become
a necessary criterion to be evaluated before any significant construction nowadays (Arango et al.,
2000; James et al., 2013). Liquefaction of soils is the conversion of formerly stable cohesionless soils
to a fluid mass due to increased pore water pressure. It is majorly observed in areas which have the
water table close to the surface and have sandy soils (Marcuson, 1978). The dynamic loading of the
earthquake causes pore water pressure to increase, which triggers the soil to behave like a liquid. A
great example of liquefaction induced disasters would be the three-month duration of 1964 in which
the Good Friday earthquake in Alaska (M
w
= 9.2) and the Niigata earthquake in Japan (M
s
= 7.5)
(Seed and Idriss, 1967; Kawasumi, 1968; Hansen et al., 1966; Kramer, 2007) had occurred. Both
the earthquakes caused catastrophic damage to all kinds of structures due to liquefaction. Since
then, extensive research has been carried out in this field to prevent any such devastating calamities