TITLE:
Use of GIS Based Maps for Preliminary Assessment of Subsoil of Guwahati City
AUTHORS:
Binu Sharma, Shaffi Kamal Rahman
KEYWORDS:
Standard Penetration Test, Shear Wave Velocity, Contour Map, GIS Based Maps, Subsurface Investigation
JOURNAL NAME:
Journal of Geoscience and Environment Protection,
Vol.4 No.5,
May
19,
2016
ABSTRACT: Guwahati, the major city in the North Eastern region of India is growing
rapidly in every aspect with major infrastructures like sports complex,
educational institutions, hospitals, flyovers, multiplex halls, etc. Knowledge
of the subsurface soil condition is necessary to ensure the structural safety
and serviceability of the above mentioned structures before any construction.
Therefore, contour maps of Standard penetration test N value, ground water
table and shear wave velocity map using Geographical Information System (GIS)
platform will be of great help to the foundation designers at the initial stage
for site selection and preliminary foundation design under static and seismic
condition. Contour maps of Standard penetration test N value at different depth
and average contour map of N value of Guwahati city have been prepared.
Standard penetration Test N values and depth of water table were taken from a
data base of 200 boreholes up to 30 meter depth to prepare N value contour map
of Guwahati city. A regression equation between shear wave velocity Vs and Standard penetration test N value based on twenty seven previous similar
correlations was also developed. This regression equation was used to determine
shear wave velocity of Guwahati city. The average shear wave velocities for 30
m depth for all locations had been determined and used to generate map on (GIS)
platform. Other subsurface geotechnical information of Guwahati city like soil
classification and depth to water level from ground surface is also presented in
the form of GIS based maps in order to form a data base.