Estimating Driven Pile Side Resistance from SPT-Torque Tests

Abstract

Despite its many perceived shortcomings, the Standard Penetration Test remains the most common site investigation tool used throughout the world. The results from the SPT are often used to estimate side resistance of piles. The SPT- Torque Test or SPT-T is a simple modification to the SPT in which the traditional SPT is complemented by a torque measurement after driving the split spoon to give a more direct measurement of side resistance between the soil and the spoon. SPT-T tests performed at a number of sites demonstrate that the results obtained from the SPT-T may be used to estimate pile side resistance much in the same way that the CPT friction sleeve is used. The results show a direct correlation between SPT N60-values and unit side resistance. This is consistent with observations reported in the literature relating N to side resistance of full scale piles. The results are used to provide some reasoning for the apparent correlations reported in the literature and suggest that the SPT-T can be a valuable test for making preliminary estimates of pile side resistance. ABSTRACT: Despite its many perceived shortcomings, the Standard Penetration Test remains the most common site investigation tool used throughout the world. The results from the SPT are often used to estimate side resistance of piles. The SPT- Torque Test or SPT-T is a simple modification to the SPT in which the traditional SPT is complemented by a torque measurement after driving the split spoon to give a more direct measurement of side resistance between the soil and the spoon. SPT-T tests performed at a number of sites demonstrate that the results obtained from the SPT-T may be used to estimate pile side resistance much in the same way that the CPT friction sleeve is used. The results show a direct correlation between SPT N60-values and unit side resistance. This is consistent with observations reported in the literature relating N to side resistance of full scale piles. The results are used to provide some reasoning for the apparent correlations reported in the literature and suggest that the SPT-T can be a valuable test for making preliminary estimates of pile side resistance.