مشخصات پژوهش

The design of geotechnical structure acting under multi-axial loading requires knowledge about the soil behavior under intermediate principal stress. Even though conducting the numerous experiments and numerical researches about the behavior of common standard silica soils under 3-D loading, few investigations are made for soils with the dilative behavior. This paper aims to study the behavior of Bushehr carbonate sand from a north shelf of Persian Gulf under various intermediate principal stresses by conducting the hollow torsional shear tests. The test result implies that the plane strain condition occurs when an intermediate principal parameter (b) is equal to 0.3. Under this condition, soil gets the maximum value in ultimate negative pore water pressure, ultimate deviatoric strain, effective frictional angle and the radial strain becomes close to zero. Maximum radial strain and minimum deviatoric strain occur under the triaxial condition where the b is 0. Besides, under b = 0 condition, soil has the lowest value of ultimate negative pore water pressure and effective friction angle. The considerable effect of intermediate principal stress on the soil behavior is found in samples packed with loose state.