Nonlinear Regression Analysis for Side Resistance of Socketed Piles in Rock Formations of Dubai Area

Pile capacity installed in Dubai rock formation is calculated based primarily on socket shaft resistance. During preliminary design, socket resistance is estimated by using correlations with rock strength that do not reflect the behavior of Dubai rock formations as well as construction practices. Consequently, large discrepancy is often noticed between predicted pile capacity and that determined from the results of pile load tests. In this study, a new predictive model is developed for socket shaft resistance of piles constructed in rock formations of Dubai area. Five (5) instrumented piles of different diameters and socket lengths ranging from 10 to 15m are tested. The proposed model takes into account the compressive strength of the rock in addition to the pile movement at the top of socket to predict its side resistance. The average side resistance of the socket predicted using the proposed model compared well with the results of load transfer along the sockets of the test piles. In addition, the developed model is compared with published models from other regions to illustrate the area specific nature of correlations and factors that affect their generality are highlighted.