Describes an investigation of the 2x2 model pile groups embedded in clay bed, with floating pile cap, subjected to vertical working loads. The experimental results were compared with elastic continuum analysis (PGROUP) using homogeneous and non-homogeneous soil model. The comparisons suggest that non-homogeneous soil model (the shear modulus varying linearly with depth) is more appropriate than homogeneous model (modulus remain constant) for the clay bed. The elastic response of pile groups could be predicted on the basis of shear modulus evaluated from single pile load tests.