Geotechnical Investigation for Estimation of Liquefaction Hazard for the Capital City of Gujarat State, Western India
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ORIGINAL PAPER
Geotechnical Investigation for Estimation of Liquefaction Hazard for the Capital City of Gujarat State, Western India Vasu Pancholi . Vinay Dwivedi . N. Y. Bhatt . Pallabee Choudhury . Sumer Chopra
Received: 17 December 2019 / Accepted: 6 July 2020 Ó Springer Nature Switzerland AG 2020
Abstract Gandhinagar, the capital city of Gujarat state (Western India), is situated in the middle of the moderately active Cambay rift. The region lies under the seismic zone III of the seismic zoning map of India. The city rests on 250–300 m thick flood plain deposits consisting of coarse sand, silt and clay. In this work, liquefaction hazard is assessed using geotechnical investigations. A total of 14 boreholes of 35 to 50 m depth were drilled with sampling at every 1.5 m depth interval (till termination depth) covering entire
V. Pancholi (&) V. Dwivedi P. Choudhury S. Chopra Seismic Hazard and Microzonation Group, Institute of Seismological Research, Raisan, Gandhinagar, Gujarat, India e-mail: [email protected]
Gandhinagar city. A standard penetration test (SPT N-value) was conducted at an interval of 3 m depth in every borehole. We used 400 samples for the estimation of index properties of the soil in the study area. The lithological distribution in the city is also mapped based on the soil classification. The liquefaction hazard is estimated by standard methodologies using density, plasticity index, groundwater level, Peak Ground Acceleration (PGA), fine content and Standard penetration test (SPT) N value. The site-specific PGA values at the surface are estimated by carrying out ground response analysis. The study shows that the area comprises of alternate layers of argillaceous and arenaceous soil. We found that in general the area has low liquefaction potential but in case of heavy rainfall the chances of liquefaction may increase as the soils are conducive of liquefaction. Keywords Geotechnical investigation Standard penetration test Liquefaction Seismic hazard analysis
V. Dwivedi e-mail: [email protected] P. Choudhury e-mail: [email protected]
1 Introduction
S. Chopra e-mail: [email protected]
Earthquake is the natural calamity that cannot be forecasted. If earthquakes cannot be prevented or predicted, then society needs to learn to live with them. For this purpose, proper assessment of the
N. Y. Bhatt M.G. Science Institute, Ahmedabad, Gujarat, India e-mail: [email protected]
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Geotech Geol Eng
seismic hazard of a region is necessary that may prevent the loss of human lives and property by taking proper mitigation measures before an impending earthquake. Proper land-use planning and following appropriate construction practices using earthquakeresistant design can minimize the severity of the damage. Liquefaction is the main reason for ground failure during an earthquake. Liquefaction is a process in which the earthquake shaking reduces the strength and stiffness of the saturated sand and other granular materials due to
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