Hello, I am writting to ask how to get the elastic modulus or undrained strength of the soil in the simulation model by using hypoplastic model in clay? Is there any formula that can be calculated from the hypoplastic model parameters, or is there some other way?Thank you so much.

Undrained shear strength is calculated using Hypoplastic model by the combination of state dependent variables SDV7, SDV9, SDV15 i.e. Void ration , Effective stress and OCR using equation…using equation
Su=o.18(σ’v)OCR^0.9….. Further the relation between these state dependent variables can be found in the the chapter 6 of the book of Dr. David masin”Modelling of of soil behavior with hypoplastcity’
e=expN−λ∗ln(OCR∗p) −1
Good luck and thank you

2. David Mašín 2 years ago

Hi Muhammad, thanks for replying. And Wenbo: For clarification, the formula for undrained shear strengh (Eq. 6.22 from the book Masin, 2019) is cu=p*M*OCR/4, where M=6*sin phic/(3-sin phic) and OCR=pe/p with pe=exp((N-ln(1+e))/lambda). Elastic modulus is only defined for small strain stiffness version of the model (the one with intergranular strain), where the shear modulus G0=Ag(p/pr)^ng with pr=1 kPa.

• Wenbo Gu 2 years ago

Thank you for your clarification Prof. Mašín !

• Baban Bapir 1 year ago

Dear all,

Im simulating an undrained triaxial test in Abaqus, I can get the strain tensor from state variables 1-6, but I don’t know how to get the stress tensor.
shall we calculate it from default the stress components of Abaqus, or we should calculate it based on state variable outputs?