In pile - soil interaction analysis, the slippage and separation of pile from the soil contact can be simulated in PLAXIS software using interface. The interface behaviour between pile and soil can be defined by using normal and shear stiffness. In PLAXIS this can be simulated indirectly defining the interface factor for pile and soil..In soil model use advanced option from here define the intreface factor for pile is 1 and for soil is 0.67..ok all the best in your research..