Comparison of Ultimate Pile Capacity for Bored Piles Using Field Interpretation, Theoretical and Numerical Methods

Abstract

The geotechnical design of pile foundation is based on determination of geometric design followed by calculation of ultimate pile capacity either by theoretical or empirical methods which are further required to be validated by pile load tests. Mostly piles are not loaded until failure in pile load test owing to test time and cost involved. Therefore, different interpretation methods have been formulated to analyze load settlement curves obtained from pile load testing for prediction of ultimate capacity. Interpretation methods have unique assumptions as well as some limitations and therefore give varied results. A database of 93 static piled load tests, conducted on axially loaded bored concrete piles, has been studied to ascertain suitable method for prediction of ultimate pile capacity. 43 static pile load tests compiled in Pile Database A have been analyzed for comparison of ultimate capacity between theoretical methods, twelve pile load test interpretation techniques and numerical pile capacity by PLAXIS 3D. Failure criteria for bored piles modelled in PLAXIS 3D is based on pile head settlement equal to 8 % of pile diameter which has been formulated by analysis of Pile Database B having 50 bored piles loaded until failure. The test results indicate that DeBeer and Mazurkiewicz methods give results close to the maximum test load in pile load test. Average value of Debeer and Mazurkiewicz methods varies by 4.16 % when compared with maximum test load applied in static pile load test and therefore reliable for prediction of ultimate pile capacity.