Abstract: Hardening-soil model, which was based on shear and volumetric yielding mechanism, has been widely applied to geotechnical engineering due to its relative accuracy in the reflection of complex stress path of the soil. However, misunderstanding of its volumetric mechanism widely existed in related domestic research. And the description of its inner parameter solution algorithm is not correct, thus its advantage in simulating the uniaxial compression and K0 consolidation process cannot be reflected. Based on the discussion of the meaning of its inner parameters which controlled its volumetric yielding and hardening, its volumetric yield mechanism is explained in detail; and the explicit analytical solution of these two parameters is also given. Furthermore, a modified Euler mid-point integration method is employed for the constitutive integration procedure since there exists numerical implementation difficulty caused by both of nonlinear elasticity and multi-yield surface plasticity of HS model, and the above work has also been testified by the experimental and numerical results of relevant reference.

Key words: hardening-soil model, volumetric yielding mechanism, theoretical analysis, constitutive integration algorithm