If the infiltration intensity is less then the saturated permeability coefficient, the surface soil finally reaches to an unsaturated infiltration stage instead of saturated infiltration stage.

• 当降雨强度小于土体的饱和渗透系数时，表层土体达不到饱和状态，最终的稳定入渗只能达到一个非饱和入渗状态。