Abstract: A simplified consolidation theory for unsaturated soils was proposed based on an assumption that pore air pressure equaled to the atmosphere pressure.A finite element computer program for saturated soils was revised accordingly in order to be used in the analysis of crack formation and propagation upon drying on the clay surface.In numerical simulation,the distribution of polygonal cracks was simplified as an axisymmetrical problem with a double hardening elasto-plastic model adopted for soil skeleton.The sensitivities of various parameters to the width and depth of cracks developed were also studied.