Settlement of Axially Loaded Pile Groups in Inhomogeneous Soil-Article

Article

Pdf Summary

The paper develops a practical method for predicting settlement in axially loaded pile groups embedded in soil whose stiffness varies with depth. It extends the pile-interaction approach of Mylonakis and Gazetas, in which the influence of one loaded “source” pile on an unloaded “receiver” pile is represented by an interaction factor. The analysis uses a Winkler model and assumes soil stiffness follows a power-law depth profile.<br /><br />The authors derive a closed-form solution for interaction factors in inhomogeneous soils. Although this solution is suitable for design software, its Bessel functions make it inconvenient for hand calculations. They therefore assess an approximation that replaces the soil profile with an equivalent homogeneous stiffness and introduce a model-error correction factor to improve its accuracy. The corrected approximation predicts the analytical solution to within 10% for most practical configurations.<br /><br />An illustrative four-pile example shows that group settlement can substantially exceed the settlement of a single pile carrying the same average load. The paper also tests the method against a published nine-pile field test: predicted load distribution among corner, side, and centre piles agrees well with measurements and previous analyses, while estimated settlement is close to the observed value.<br /><br />Overall, the proposed method offers a relatively simple alternative to full three-dimensional numerical analysis for estimating pile-group settlement in soils with depth-dependent stiffness.

Keywords

pile groups

settlement prediction

axially loaded piles

soil stiffness variation

Winkler model

interaction factors

power-law soil profile

Bessel functions

model-error correction

pile-group settlement