Shear load transfer characteristics of drilled shafts in weathered rocks

The load distribution and deformation of drilled shafts subjected to axial loads were evaluated by a load-transfer approach. The emphasis was on quant ifying the load-transfer mechanism at the interface between the shafts and surrounding highly weathered rocks based on a numerical analysis and on sma ll-scale tension load tests performed on nine instrumented piles. An analyt ical method that takes into account the soil coupling effect was developed using a modified Mindlin's point load solution. Based on the analysis, a si ngle-modified hyperbolic model is proposed for the shear transfer function of drilled shafts in highly weathered rocks. Through comparisons with field case studies, it is found that the prediction by the present approach is i n good agreement with the general trend observed by in situ measurements, a nd thus represents a significant improvement in the prediction of load defl ections of drilled shafts.