Based on the principle of effective stress of unsaturated soil expressed by intergranular suction stress combined with experimental data, the critical state lines under different matric suctions are unified into a single straight line. Based on this result, a new unsaturated soil dilatancy equation is proposed. First, combined with orthogonal conditions, the average effective stress and generalized shear stress are used as stress parameters to obtain the plastic potential function. Second, an incremental elastoplastic constitutive model is derived by using the yield surface of the modified Cam-Clay model and non-associated flow rule; the new constitutive model reduces to the modified Cam-Clay model for saturated soil. Stress–strain curves calculated by the model are compared with experimental results for different stress paths. The results of the comparison show that the elastoplastic constitutive model established in this work can accurately predict the stress–strain relationship of unsaturated soils.
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Translated from Osnovaniya, Fundamenty i Mekhanika Gruntov, No. 1, January-February, 2022.
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Zhou, F., Shao, Y. & Ahmed, M.A.I. An Elastoplastic Constitutive Model for Unsaturated Soils Using the Suction Stress Variable. Soil Mech Found Eng 59, 23–31 (2022). https://doi.org/10.1007/s11204-022-09780-0
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DOI: https://doi.org/10.1007/s11204-022-09780-0