The Bhuj, India, earthquake: lessons learned for earthquake safety of dams on alluvium

• Published in: Engineering geology Vol. 66; no. 3; pp. 163 - 196
• Main Authors: Krinitzsky, Ellis L, Hynes, Mary E
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01.11.2002; Elsevier
• Subjects: Alluvium; Applied sciences; Bhuj, India; Buildings. Public works; Dams; Dams and subsidiary installations; Earth sciences; Earth, ocean, space; Earthquake; Earthquakes, seismology; Exact sciences and technology; Foundations; Geotechnics; Hydraulic constructions; Internal geophysics; Kachchh; Soil liquefaction; Structure-soil interaction; Asia; India; Foundations; Dams; Earthquake; Kachchh; Bhuj, India; Soil liquefaction; Alluvium; Subgrade; Liquefaction; 2001; Tectonics; Dam; Experience; Granular soil; Earthquakes; Failure analysis; Structure soil interaction; Saturated soil; Strength
• ISSN: 0013-7952; 1872-6917
• DOI: 10.1016/S0013-7952(02)00049-2

The Bhuj, India, earthquake of 26 January 2001, M s 7.9, caused dams built on alluvium to sustain damage ranging from cosmetic to severe. Major damage was caused almost entirely by soil liquefaction in the alluvium. The critical factor was the level of earthquake ground motion. The Bhuj earthquake showed that peak horizontal accelerations (PHAs)≤0.2 g were generally safe. PHAs>0.2 g were hazardous, when unconsolidated granular foundation soils were water saturated. N values of <20 are indicative of susceptibility to soil liquefaction. The Bhuj experience showed that alluvial foundation soils, subject to a PHA>0.2 g, must be evaluated over the full area beneath a new dam and all soils deemed susceptible to liquefaction must be either removed or treated. For remediating an old dam, reliable options are removal and replacement of liquefiable alluvium beneath upstream and downstream portions of the dam, combined with building berms designed to provide stability for the dam should there be a strength loss in soils beneath the dam.