The zero thickness interface element

which based on the framework of elastoplastic constitutive model

is convenient to implement in finite element code in the similar way as used for small-displacement material nonlinear problem

and is used widely to analysis the interaction between soil and structure. The integration algorithm of constitutive equation is a key issue for finite element computation. The integration method for three kinds of contact behaviors is discussed based on the non-associative or associative linear elastic perfectly plastic model

yielding with Mohr-Coulomb failure criterion. A pair of pseudo yielding function and potential function is introduced

in order to renew the stress that violate the yielding criterion and locate in the apex area of yielding surface. According to this method

a self-adaptive sub-stepping integration algorithm using back-Euler method is implemented in ABAQUS user defined element subroutine. Two examples are analyzed

using this code

to examine the ability of this algorithm to model three type interaction behavior. The results

which agree well with theory’s and limit analysis’s ones

show that the algorithm is effective.