Side Resistance of Drilled Shafts Socketed into Rocks for Serviceability and Ultimate Limit States

Abstract

This study evaluates the analysis models of side resistance in rock sections by utilizing a wide variety of load test data. Available analytical models including the empirical adhesion factor versus the rock’s uniaxial compressive strength and its root are analyzed and compared statistically to determine the optimum relationships. The interpretation criteria for the L1 and L2 methods are used to analyze the load test results for serviceability and ultimate limit states, respectively. The analysis results show that the relationship model with the empirical adhesion factor versus the root of the rock’s uniaxial compressive strength exhibits better correlation than the one with the rock’s uniaxial compressive strength. Moreover, the general coordinate axes regression equation demonstrates better reliability than the semi-logarithmic and full logarithmic axes equations for both limit states. Based on these analyses, specific design recommendations for the side resistance of drilled shafts socketed into rocks are developed and provided with the appropriate statistics to verify their reliability.