End Bearing Behavior of Drilled Shafts in Rock

The end bearing behavior of piles socketed in weathered/soft rock is generally dependent upon the mass conditions of rock with fractures rather than the strength of intact rock. However, there are available data and little guidance in the prediction of the end bearing capacity of drilled shafts socketed in weathered/soft rock, considering rock mass weathering. Therefore, a database of 13 load tests was constructed first, and new empirical relationships between the base reaction modulus of piles in rock and rock mass properties were developed. No correlation was found between the compressive strengths of intact rock and the base reaction modulus of weathered/soft rock. The ground investigation data regarding the rock mass conditions(e,g, Em Eur, RMR, RQD) was found to be highly correlated with the base reaction modulus, showing the coefficients of correlation greather than 0.7 in most cases. Additinally, the applicability of existing methods for the end bearing capacity of pile in rock was verified by comparison with the field test data