Shear load transfer characteristics of drilled shafts socketed in rocks: Fid-Bau Portal

Shear load transfer characteristics of drilled shafts socketed in rocks

Jeong, S. / Ahn, S. / Seol, H.

In South Korea, a number of large construction projects, such as land reclamation for an international airport, highspeed railways, and harbor construction, are in progress in urban and coastal areas. Drilled shafts are frequently used in those areas as a viable replacement for driven piles for two applications: deepwater offshore foundations and foundations in urban areas where noise and vibration are not tolerated. Over 90 % of the drilled shafts constructed in South Korea are embedded in weathered or soft rocks. This paper presents a shear load transfer function and an analytical method for estimating the load transfer characteristics of rock-socketed drilled shafts subjected to axial loads. A shear load transfer (f-w) function of rock-socketed drilled shafts is proposed based on the constant normal stiffness (CNS) direct shear tests. It is presented in terms of the borehole roughness and the geological strength index (GSI) so that the structural discontinuities and the surface conditions of the rock mass can be considered. An analytical method that takes into account the coupled soil resistance effects is proposed using a modified Mindlin's point load solution. Through comparisons with load test results, the proposed methodology is in good agreement with the general trend observed in in situ measurements and represents an improvement in the prediction of the shear behavior of rock-socketed drilled shafts.