P-Y CURVES IN LAYERED SOILS (GEOTECHNICAL, STRUCTURE INTERACTION, FOUNDATIONS, PILES)

The dissertation describes research aimed at defining the resistance that layered soils offer to the lateral movement of a pile foundation. The resistance is the p and the movement is the y of a p-y curve. Criteria have existed for a number of years for describing the resistance in homogeneous soils and this past work was used and extended. Limit-equilibrium methods which characterize the soils as rigid-plastic materials were used to estimate the ultimate values of the resistance. Finite-element analyses using an axisymmetric model gave indications of the behavior that should be seen in carefully measured results of lateral loading on piles. A series of small-scale tests performed by the writer agreed qualitatively with the predictions of the analyses that used limit-equilibrium and finite elements. Results of a field test performed in layered soils by others were also examined in the framework of the conclusions based on the small-scale tests and analyses. Methods of predicting p-y curves in layered soils were presented for use in design of pile foundations and were used to make simulations which agreed well with the results of the small-scale tests and the field test.