Dilation and particle breakage effects on the shear strength of calcareous sands based on energy aspects

In this paper shear behavior of two calcareous sands having different physical properties areinvestigated using drained and undrained triaxial tests. the investigated sands are obtainedfrom two differentzones located in persian gulf, kish island and tonbak region. analysis based on energy aspects show thatfriction angle in these soils, having crushable particles. is formed of three components: substantial internalfriction angle, dilation and particle breakage angle. dilation component is available in the two investigatedsand. particle breakage component is a junction oj grains hardness, structure and geometry shape. particlesbreakage decreases the volume of sample during drained tests and creates positive pore water pressure duringundrained tests. two investigated sands show different amount ofdilution and particle breakage under similarconditions. simultaneous dilation and particles crushing and different amount ofthem result in different shearbehavior of the two studied sands. energy aspects are used to determine the effect ojparticle crushing on theshear strength. there is a suitable compatibility between relative breakage of grains and consumed energyratio for particle breakage.