Expansive soil is one of the major causes of damage on the rigid pavement. The problem with this kind of soil is non-uniform vertical displacement and low bearing capacity. Nailed slab system has been developed as an alternative rigid pavement on expansive soil. The interaction among soil, concrete slab, and piles can increase the bearing capacity dan stiffer pavement structure. This research aim to obtain a variety of the value of kV and Δkv from the single pile and group piles which will produce deflection similar to a laboratory test. The SAP2000 computer program was used as a finite element tool, and the soil is represented by the spring element. The results of finite element model was validated by model of a laboratory test. The result show that modeling with SAP2000 is suitable for small load and medium load on nailed slab system. This study confirms that finite element model using a pile with the value of the modulus of subgrade reaction by back analysis with 1,02-1,15 ksingle pile dan 0,86 klaboratory on dry condition and 1,75-4,6 ksingle pile dan 1,04-1,14 klaboratory on wet condition was closed to the laboratory model.