Evaluation of the Capacity of Bored Piles In Some Sudanese Soils Using Penetration and Pile Load Tests

Abstract

This study aims to predict the bearing capacity of bored piles installed in some Sudanese soils by evaluating pile load test results using known interpretation methods. The study also aims to develop correlations between the ultimate bearing capacity components of instrumented bored piles and the data obtained from in situ penetration tests (CPT- SPT), and compares the ultimate pile capacity values evaluated from present study results with those proposed in previous studies. A suitable study site was selected and prepared for carrying out the test program comprising of installing and testing of eight instrumented bored piles under axial static maintained loads to failure, borehole drilling and static cone penetration test (CPT) soundings were performed at adjacent points to the tested piles. Strain gauges and fabricated load cells instrumentations were utilized to enable separate determination of the shaft friction and end bearing components of the test piles in different soil strata. Statistical analysis of the pile load test results was used to evaluate the performance of seven interpretation methods of load test results selected from those published in literature. Comparisons were made between the measured bearing capacities in this study and predicted of tested piles; the results showed that the Fuller and Hoy’s method is rated as the most accurate and reliable method. Empirical correlations have been developed the skin friction and end bearing components of pile capacity on one hand and the CPT and SPT data on the other. Moreover, a comparative study was made to evaluate the suitability of the developed correlations using five different published bored pile capacity prediction methods based on the CPT and SPT data. It was found that the ultimate pile capacities determined from the present study compared well with the some previous methods based on CPT data and SPT-N values.