The author agrees with the statement that cyclic loading under undrained conditions will cause pore pressure increases in saturated soils, but disagrees that an increase in pore pressure produces a decrease in the undrained shear strength of a dilative sand. It cannot be assumed that the undrained shear strength of a dilative sand occurs when the stresses reach the strength envelope since dilation will cause the state of stress to move upwards along the strength envelope until either cavitation occurs or the critical state is reached. For the undrained behavior of medium dense or dense sands the strains at which the strength envelope is reached are quite small and thus one should take into account the usually large additional shear resistance that can develop by dilation with little change in the mobilized friction angle. The tendency for dilation is not lost as a result of increasing the pore pressures by means of cyclic loading. Comments are also made regarding observations relating to boundaries where field evidences of the behavior of saturated sands are plotted solely as a function of 2 parameters; the factor to account for different earthquake durations; and camparison of shaking table data and field data.

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Filing Info

  • Accession Number: 00149208
  • Record Type: Publication
  • Report/Paper Numbers: ASCE #11388
  • Files: TRIS
  • Created Date: Mar 30 1977 12:00AM