Toe-Bearing Capacity of Precast Concrete Piles through Biogrouting Improvement

This technical paper investigates the bearing performance of precast concrete piles embedded within calcareous sands with biogrouting at the pile toe. Loading tests of biogrout-improved and unimproved concrete model piles were conducted to evaluate the performance of biogrout to enhance the toe bearing capacity of precast concrete piles. The total bearing capacity of the precast concrete pile with a biogrouted toe was 4.4 times as large as that without biogrout. A series of index tests were performed using a penetrometer to estimate the spatial distribution of strength of biocemented sands below the pile toe. It was found that the average strength of the biocemented sand below the biogrouted pile toe gradually decreased with increasing vertical distance or lateral distance from the pile toe. The novel application of biocement to treat bearing sands following pile installation represents a promising method to increase pile capacity.