Predicting the Side Resistance of Piles Using a Genetic Algorithm and SPT N-Values

ABSTRACT: A genetic algorithm (GA) was developed to predict the side resistance of piles in Ontario with the standard penetration test blowcounts (SPT N-values). Pile foundations commonly support structures by transferring loads deeper into the ground; unfortunately, the soil characteristics, such as the strength and grain-size distribution, are rarely consistent at a site. Due to the spatial variability of the soil, challenges arise to accurately predict the ultimate axial capacity of piles. This research aims to mitigate this problem by implementing genetic programming. Since the 1950s, the Ministry of Transportation of Ontario has gathered approximately 100 pile load tests in various soil conditions, and a total of 23 piles were selected for this study. These piles were either H piles or pipe piles and were subjected to extension load tests. A GA was created to correlate the side resistances to the SPT N-values, and the developed relationships were compared to existing design methods for different soil types. In all, the ultimate goal of this research was to improve local pile design in Ontario’s practice.