Saturated Sand Samples Research Articles

A possible continuum theory for densification and liquefaction of saturated sand

A previously developed continuum theory of granular media is applied to the problems of densification and liquefaction of saturated sand. An expression for the free energy of saturated sand is developed. The process of densification of sand subjected to cyclic shear stress is studied and several expressions for an increase of the solid volume fraction are obtained and discussed. The problem of the initial liquefaction of saturated sand samples under cyclic shear stress is then considered and several criteria relating the shear stress amplitude, over-burden pressure, time to liquefaction, and physical properties of the sand sample are established. Some semiempirical relations for field applications are also presented.

Significance of formation factor in sand structure characterization

The formation factor F, obtained by electrical conductivity measurements of saturated sand samples, has been recently correlated with the liquefaction behavior of sands (2). The significance of F as a parameter obtained by nondestructive technique is discussed here, showing its capability to characterize the structure of anisotropic sand aggregates.

Sand Liquefaction In Hollow Cylinder Torsion Under Irregular Excitation

Dynamic torsion shear tests on hollow cylindrical samples of saturated sand were conducted by incorporating the test apparatus into an electrohydraulic type loading system in which any desired form of load time history can be applied to the specimen. The acceleration records taken during the recent major earthquakes were used as representative time histories in the test programs. For the several wave forms used relationships were established between the amplitude of shear stress and the residual pore pressures, which may be used to assess the dynamic pore pressures under irregular loading conditions. Finally, the results of dynamic torsion shear tests were compared with the corresponding behavior in dynamic triaxial tests and the correlation between them are discussed.