Document Type : Research Paper
Author
Lecturer, Building and construction Eng. Department, University of Technology.
Abstract
Abstract Due mainly to the process of deposition under earth gravity , the behavior of in situ sand is inherently anisotropic , meaning the stress - strain - strength relations for the same sand may vary as the stress tensor rotates relative to the orientation of the soil fabric . In this paper , the kinematic double hardening model ALTERNAT is applied to simulate the cyclic behaviour of sand . The model can describe several phenomena of sand behaviour such as the stress dilatancy , hardening , densification and cyclic mobility . The effect of initial stress anisotropy through the values of the coefficient of lateral stress at rest ( Ko ) is studied . It is concluded that the maximum shear strain increases with the increase of the coefficient of lateral stress at rest . On the other hand , the maximum spherical ( volumetric ) strain decreases with the increase of the coefficient of lateral stress at rest until a value of about ( Ko - 0.72 ) is reached , above this value , the maximum spherical strain increases . This behaviour reflects the stress dilatancy that takes place in dense sand where the values of Ko are high . The stress dilatancy increases as the value of Ko increases at the start of loading . As the number of increments increases , the effect of Ko decreases . This can be attributed to the densification that might take place under cyclic loading till the sand reaches a stable condition .
Keywords
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