A Method for Predicting Base Resistance of Drilled Shafts in Disturbed Rock Mass

Conventional methods for estimating the base resistance of rock-socketed drilled shafts simply use the unconfined compressive strength of intact rock, although the base resistance also depends on in-situ rock mass characteristics. In this study, an improved method for determining the base resistance of drilled shafts socketed in disturbed rock masses is presented. The method is based on a finite element limit analysis with the Hoek–Brown (HB) failure criterion that is applicable to both the intact and jointed rocks. The method also emphasizes the importance of disturbance and unit weight of the rock mass. A database of base resistance from load tests with available rock properties are compiled from the literature, which is used for method validation. Comparison to the measured rock-socket base resistance indicates that the proposed method produces satisfactory predictions.