Analytical calculation of laterally loaded piles in double-layered elastoplastic soils

The analytical calculations of laterally loaded piles in double-layered elastoplastic soils are relatively few at present. Based on the subgrade reaction method and the simplified elastoplastic constitutive relations of soils beside the pile, the closed-form solutions for a free-head laterally loaded long pile in double-layered, non-homogeneous elastoplastic soils are deduced, and the formulas of the plastic zone thickness of the soil, the maximum deflection and moment of the pile are derived. When some parameters take special values, the present solutions are fully consistent with the existing solutions for the piles in one-layer soil, and the correctness of the present analytical derivation is verified meanwhile. The analyses of examples show that the results calculated by the proposed analytical solutions agree with those of 3D finite element analysis and field measurements, so the present method is capable of analyzing laterally loaded long piles in double-layered soils.