Evaluation of Compression Interpretation Criteria for Drilled Shafts Socketed into Rocks

Representative compression interpretation criteria were analysed in this study to assess their relative merits and interrelationships when applied to drilled shafts socketed into rocks. Results of load tests around the world were gathered and collated into a database CYCU/RockSocket/50 for the assessment. Each of the applied interpretation criteria was then evaluated and compared with one another and with the results of the interpretations of drilled shafts in varying soil conditions and post-grouted drilled shafts. To further assess the behaviour of drilled shafts socketed into rocks, interpreted side and end bearing resistances were also determined. The mean interpreted capacities and displacements were higher for drilled shafts socketed into rocks when compared to drilled shafts in soils, but are at comparable ranges with tip post-grouted drilled shafts. On this basis, recommendations regarding specific interpretation criteria, which are advantageous for design displacement requirements under 12 mm for serviceability and displacements on the range of 53 mm to 71 mm for ultimate limit states, were established. Finally, behavioural assessments of the normalized load-displacement curves were extensively done using hyperbolic equations to test their effectivity to CYCU/RockSocket/50.