Point bearing stiffness and strength of socketted drilled shafts in Korean rocks

The load distribution and deformation of rock-socketted drilled shafts subjected to axial loads were evaluated via a load-transfer approach to quantify the point bearing load transfer characteristics of rock-socketted drilled shafts based on Hoek-cell triaxial compressive tests and a three-dimensional numerical analysis with varying rock strengths and rock mass conditions. It was found that the ultimate unit point resistance (qmax) was influenced by rock mass discontinuities; moreover, the initial tangent of the point bearing load transfer curve (Gi) was highly dependent on the rock mass modulus and pile diameter. Thus, a point bearing load transfer function for drilled shafts socketted into rock is proposed. Through comparison with the results of field loading tests, it was found that the point load transfer function proposed in the present study is in good agreement with the general trend observed by field loading tests.