A Constitutive Model for Soils Evaluating Principal Stress Rotation and Its Application to Some Deformation Problems

• Published in: SOILS AND FOUNDATIONS Vol. 30; no. 1; pp. 142 - 154
• Main Authors: Matsuoka, Hajime, Suzuki, Yasuyuki, Murata, Takanori
• Format: Journal Article
• Language: English
• Published: Tokyo Elsevier B.V 01.03.1990; The Japanese Geotechnical Society; Japanese Geotechnical Society
• Subjects: angle of internal friction; constitutive equation of soil; dilatancy; Earth sciences; Earth, ocean, space; Engineering and environment geology. Geothermics; Engineering geology; Exact sciences and technology; finite element method; granular material; sand; special shear test; stress path; stress-strain curve (IGC : D6/E2); stress-strain curve (IGC: D 6/E 2); sand; dilatancy; finite element method; stress path; granular material; angle of internal friction; stress-strain curve (IGC: D 6/E 2); constitutive equation of soil; special shear test; Deformation; Shear tests; Sand; Sedimentary rocks; Granular materials; Models; Friction angles; Finite element analysis; Soil mechanics; Rotation; Stress; Clastic sediments
• ISSN: 0038-0806; 0385-1621
• DOI: 10.3208/sandf1972.30.142

A constitutive model for soils by which the strain increments (dɛx, dɛy and dγxy) are directly related to the stress increments (dσx, dσy and dτxy) is proposed. The stress-strain matrix between the strain increments and the stress increments is expressed in xy-coordinates fixed arbitrarily. In order to evaluate the influence of rotation of the principal stress axes on strains, “principal stress rotation tests” with several rotation times, in which the stress path circles several times along the circumference of a Mohr’s stress circle, are carried out by a “two-dimensional arbitrary stress apparatus” using a stack of aluminium rods. The “arbitrary” stress path dependency of strains is also examined by the same apparatus, and analyzed by the proposed model. The finite element analysis of soil foundation under a uniform strip load is performed using the proposed model, and the influence of rotation of the principal stress axes on settlements and lateral displacements is checked by comparing the computed results under different contribution factors (5% to 100%) of strains due to rotation of the principal stress axes. It is seen from the computed results that the settlements and lateral displacements are influenced significantly by the principal stress rotation.