Side Resistance of Drilled Shafts Socketed into Grouted Mine Workings

Site investigation revealed that abandoned coal mine workings were present under a site planned for construction of a major new facility. After the mine workings were remediated through void fill grouting, drilled shafts were installed at the site, with sockets into the shale encountered both above and below the grouted mine voids. To evaluate the axial load capacity, O-Cell load testing was performed on these drilled shafts. Based on the test results, the unit side resistance of the rock sockets is back-calculated and compared with those estimated using empirical methods.