Rationality of load transfer approach for pile analysis

New closed form solutions accounting for non-homogeneous, elastic plastic o r visco-elastic soil properties have been established for a single pile sub jected to vertical loading, and for vertically loaded pile groups. The solu tions are based on load transfer approach, with the pile-soil interaction b eing characterised by springs distributed down the pile shaft and at the pi le base. As such, the accuracy of the solutions lie in the load transfer fa ctors linking the gradient of the load transfer curves with elastic modulus values. This paper presents an extensive investigation into the load trans fer approach, by comparing the new closed-form solutions for a pile embedde d in an elastic medium with rigorous numerical analysis. By this means: 1. The rationality of the load transfer approach has been extensively explored ; 2. Load transfer factors have been calibrated against the numerical solut ions to account for a number of factors, such as the ratio of the depth to the underlying rigid layer and the pile length, the degree of soil non-homo geneity, Poisson's ratio for the soil, and the pile slenderness ratio; 3. E xpressions for estimating the load transfer factors have been provided. Wit h the new load transfer factors, the closed form solutions may be applied w ith high accuracy over a very wide range of pile geometries and soil condit ions. (C) 1998 Elsevier Science Ltd. All rights reserved.