Liquefaction Mitigation â€“ Indian practice and recent studies-Poster Upload

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The paper reviews liquefaction mitigation practices in India and recent research. Liquefaction occurs when earthquake shaking raises pore-water pressure in saturated sandy soils, reducing effective stress and soil strength. Ground improvement can mitigate the risk by densifying soil, increasing its strength, or providing drainage.<br /><br />In India, the principal methods are vibro compaction and vibro stone columns. Vibro compaction is suited to sands with low fines content and aims to increase relative density to about 70–85%. Stone columns are widely used in loose, saturated, cohesionless soils, with design commonly based on Priebe’s method.<br /><br />Research by Rayamajhi et al. indicates that stone columns reduce cyclic shear stresses by approximately 10–30%. Assuming shear-strain compatibility substantially overestimates this benefit; Priebe’s reduction factor predicts an intermediate, but relatively higher, effect. The authors recommend distinguishing the reinforcement benefit from the separate effects of soil compaction.<br /><br />Studies also suggest that isolated stone columns are less effective for reducing liquefaction potential than lattice-type reinforcement. Deep soil mixing or jet grouting can create such grids, potentially providing stronger mitigation, including in soils that cannot be effectively compacted. The paper concludes that treatment should be selected to suit site conditions and supported by appropriate engineering design.

Keywords

liquefaction mitigation

earthquake shaking

pore-water pressure

ground improvement

vibro compaction

vibro stone columns

Priebe method

cyclic shear stress

deep soil mixing

jet grouting