ANTI LIQUEFACTION MEASURES FOR SANDY SOIL

Abstract

One of the major cause of catastrophic damages to structures during earthquakes is liquefaction of loose saturated cohesionless soils. Structures resting on such soils may experience large scale movements and differential settlements due to liquefaction of foundation soil during an earthquake. Extra safety taken in the design of the super structures may not be of any help if the site on which structure resting is prone to liquefaction. Hence it is necessary to take appropriate anti liquefaction measures for the safety of the satrectures. Bringing sand to higher density and application of a surcharge load and presence of a non liquefying clay layer are under stood to provide resistance to liquefaction. The presence investigations are carried out to study the behaviour of a non liquefying layer in between the sand on liquefaction characteristics. The test programe is run on large samples of sand deposit on a horizontal vibration table. The investigation confirms the earlier findings that initial relative density of the deposit and effective overburden pressure reduces the chance of liquefaction if these are beyond a certain value corresponds to threshold value of acceleration. It is also concluded that introduction of a non liquefying clay layer in sand deposit does not cause the reduction in liquefaction potential.