Quantitative study of performance of piles based on method of installation-Paper

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The study compares the performance of bored cast-in-situ (BCIS) non-displacement piles and driven cast-in-situ (DCIS) displacement piles at a coastal refinery site in India. Both piles were founded in similar layered silty sand and silty clay soils and assessed using routine maintained-load compression tests.<br /><br />The BCIS pile was 600 mm in diameter and 13 m long; the DCIS pile was 550 mm in diameter and 11 m long. At maximum test loads of approximately 1,087 kN and 1,179 kN, respectively, their final settlements were 7.32 mm and 5.56 mm. The DCIS pile also had lower residual settlement after unloading. Although the piles behaved similarly up to about 600 kN, the driven pile carried roughly 15% more load at 6 mm settlement despite its smaller size.<br /><br />Ultimate capacities estimated using the Chin method were 2,182 kN for the BCIS pile and 2,200 kN for the DCIS pile. The corresponding factors of safety were 2.26 and 2.14. The DCIS pile used about 40% less concrete, and its installation did not require drilling fluid.<br /><br />The results indicate that, under the tested conditions, displacement piles provided slightly better load-settlement performance and concrete efficiency than non-displacement piles. The authors therefore recommend considering DCIS piles where site conditions permit, while noting that the comparison is based on tests of only one pile of each type.

Keywords

bored cast-in-situ piles

driven cast-in-situ piles

pile load test

load-settlement behavior

coastal refinery site

silty sand

silty clay

ultimate pile capacity

Chin method

concrete efficiency