For a low embankment road

the reasonable prediction of vehicular load-induced plastic deformation plays an important role in the road design. According to the mechanism of vehicular load-induced plastic strain

the plastic strain comprises two parts: plastic volumetric strain and plastic shear strain. In the calculation of plastic volumetric strain

the dissipation equation with a source term

which couples Terzaghi’s consolidation theory with the experimentally-achieved cumulative pore pressure model under undrained condition is adopted. While in the calculation of plastic shear strain

the hardening factor of plastic volumetric strain is taken into consideration. The validity of the model is verified by the dynamic triaxial test results of saturated clay under undrained and drained condition. For practical problems

the vehicular load-induced stress is calculated by the numerical method firstly; then the plastic strain can be calculated by the proposed model. Finally

the plastic deformation is obtained by the layer summation method. The calculation example of the point NO.1 on Saga Airport access road is analyzed to illustrate the validitity of the model in a pratical boundary value problem.