Numerical study on settlement of piled foundations on homogenous rock

Settlement behavior of piled foundations on homogenous rock was investigated using an extensive three-dimensional finite element analysis of different piled-foundation models. Effects of pile slenderness ratio, pile spacing, and subgrade stiffness on such behavior were studied. In spite of having a significant number of publications on this research area, this effort is distinguished by adopting pile-subgrade stiffness ratios that simulate piled foundations on sedimentary rocks. Charts were developed to estimate the elastic settlement of piled foundations and help in choosing the optimum pile spacing and length that limit foundation settlement to tolerable levels. The study also showed that having highly stiff rock mass as subgrade for shallow foundations may make piles practically ineffective as settlement reducers regardless of their length and spacing. Settlement values yielded from the finite element analysis were compared with those calculated from equations commonly utilized in estimating elastic settlement of foundations.