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http://dx.doi.org/10.7843/kgs.2006.22.7.23

Shear Load-Transfer Function of Rock-Socketed Drilled Shafts Considering Borehole Roughness  

Seol, Hoon-Il (Dept. of Civil Engrg., Yonsei Univ.)
Woo, Sang-Yoon (Dept. of Civil Engrg., Yonsei Univ.)
Han, Keun-Taek (Civil & Environment Div., Posco E&C)
Jeong, Sang-Seom (Dept. of Civil Engrg., Yonsei Univ.)
Publication Information
Journal of the Korean Geotechnical Society / v.22, no.7, 2006 , pp. 23-35 More about this Journal
Abstract
Shear load transfer characteristics of rock-socketed drilled shafts were analyzed. The constant normal stiffness (CNS) direct shear tests were performed to identify the major influencing factors of shaft resistance, i.e., unconfined compressive strength, borehole roughness, normal stiffness, initial confining stress, and material properties. Based on the CNS tests, shear load transfer function of drilled shafts in rocks is proposed using borehole roughness and the geological strength index (GSI), which indicates discontinuity and surface condition of rock mass in Hoek-Brown criterion (1997). The proposed load-transfer function was verified by the load test results of seven rock-socketed drilled test shafts subjected to axial loads. Through comparisons of the results of load tests, it is found that the load-transfer function by the present study is in good agreement with the general trend observed by in situ measurements, and thus represents a significant improvement in the prediction of load transfer of drilled shafts.
Keywords
Borehole roughness; Constant normal stiffness; Drilled shaft; GSI; Hoek-Brown criterion; Rock-socket; Shear load transfer function;
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