Behaviour of spliced piles - A field study

In several situations use of long piles becomes necessary. The inconvenience of use of long piles can be off setted by using “Spliced Piles” provided the splices/joints between segments do not introduce weakness in piles. Since splice pile technology has not picked up in India yet, efforts have been made to develop joints for piles and thus to introduce splice technology for use in field. Four types of joints have been developed, and their performance evaluated through use of these joints in RCC precast piles installed in loose to medium dense cohesionless, and soft clay deposits. The results obtained from their field behaviour both during driving and in situ load testing have demonstrated their suitability with respect to performance under compressive, pullout and lateral loads. Further with a view to eliminate/reduce the negative drag on piles, the ambient soft clay around the piles was transformed into composite mass of low compressibility by resorting to ground treatment techniques utilizing Plain Granular Piles (PGP), Mini Grouted Piles (MGP) and Self Setting Soil Slurry Piles (SSSSP). Adoption of these techniques resulted in significant reduction in settlement of ambient ground and consequently the negative drag on piles. The introduction of bitumen slip layer also resulted in significant reduction of negative drag on piles. It is concluded that the performance Of splices developed and used with RCC segment of precast piles during driving, load testing under vertical compressive, lateral and pull out loads have been found satisfactory and in no way inferior to intact piles. This is true both for cohesionless and soft clay deposits. For reducing/eliminating negative drag all the three methods of ground treatments are effective in transforming the ambient soil mass into an improved composite soil mass.