AN INVESTIGATION OF “b VALUE” DETERMINATION AND INTERMEDIATE PRINCIPAL STRESS VARIATION IN POROUS MEDIA

This paper describes a series of drained monotonic plane strain test results on Leighton Buzzard sand under different initial magnitudes of intermediate principal stress, ?2. The variations of stress ratio ?2/(?1+?3) were monitored during shearing to clarify the significance of intermediate principal stress. It is shown that the stress-strain response of sand, its shear strength and stress ratio ?2/(?1+?3) at failure, do not vary significantly and almost independent of the initial magnitudes of ?2, but are dependent on its initial void ratio, implying that if different initial values of ?2 create various directional anisotropic structures they play no part in the plane strain tests. Also a numerical model, which is capable of including ?2, is proposed to predict particularly stressstrain response of sand and magnitude of ?2 at failure

کلیدواژه ها:

sand ، monotonic test ، intermediate principal stress ، b value ، modeling