A modified super-subloading surface model based on energy dissipation for boom clay and its numerical implementation

Due to the limitation of modified Cam-clay model, which cannot depict the over consolidated or structured clay, the concept of super-subloading surface was introduced to describe the destruction of Boom clay. According to the characteristics of the yield surface of Boom clay, the super-subloading surface model was modified based on energy dissipation. Adopting the closest point projection method(CPPM), the UMAT subroutine of the developed model was implemented in the finite element modeling code ABAQUS. With the developed model and the modified Cam-clay model, numerical simulations to the undrained triaxial compression tests on Boom clay under the different confining pressures were performed. The simulated results with two different models were compared with the test results. It was shown that the developed model depicted the destruction process of Boom clay during shearing and the peak strength of over consolidated clay decreased in compared with the super-sub loading surface model.