A hybrid strength criterion for a soil medium based on tension strength and its implementation in numerical analysis

Because of inaccurate descriptions of stress‒strain relationships for the tension–shear region of the Mohr–Coulomb strength criterion, a new hybrid strength criterion called the tension–shear strength criterion was proposed and established in this study. Based on uniaxial tensile tests (using a newly developed apparatus) and triaxial shear tests, the feature points of the failure envelopes were obtained. The tension–shear strength criterion was then derived according to these points. Subsequently, to solve the discontinuous derivatives of the singularities in the yield surface, the tension–shear strength criterion was converted into its numerical form based on a new rounded method, and a constitutive integral algorithm of the tension–shear strength criterion was given. Finally, several numerical examples with theoretical and empirical solutions were adopted to validate the effectiveness and accuracy of the numerical form of the tension–shear strength criterion.