DFI of India (DFII) has conducted an ambitious technology initiative involving the installation and testing of continuous flight auger (CFA) piles. The goal of the initiative is to introduce and popularize the use of CFA piles and to address the growing fast track piling needs of India. Two trial piles and six test piles of 600 mm (23.6 in) diameter were installed to a depth of 11.0 m (36 ft) last May at Gorakhpur village, Hisar District, Haryana, about 210kms Northwest of Delhi.
A Soilmec SR40 rig was fitted with CFAs and required ancillary equipment. DFII used Jean Lutz software to record the piling profile throughout the depth, the volume of concrete consumed, auger lifting rate and other data. M35 grade concrete was used from a site batching plant and gave a slump spread in excess of 800 mm (31 in). A rigid reinforcement cage ensured adequate rigidity for pushing in wet concrete.
Last November, static load testing was completed on the CFA piles, and involved two piles being tested for vertical compression, two for vertical pull-out and two for lateral loading. All load tests conformed to Bureau of Indian Standards (IS: 2911 (Part 4), 2013), and involved a maintained load application on an incremental basis up to a computed ultimate pile load. The goal was to assess pile ultimate load capacities and confirm safe working loads. All tests revealed that ultimate capacities are 15% to 20% higher than the estimated capacities. While this is a very positive outcome of our trials, an upward revision of design input parameters may be recommended only after more pile load tests in the future.
DFII’s CFA Pile Technology Committee is preparing a manual about the design, installation and testing of CFA piles to share with Indian geotechnical professionals through seminars and workshops.
DFI of India was formed in 2013 following the success of the Deep Foundation Technologies for Infrastructure Development in India Conference held in Chennai, India, in 2012. The Regional Chapter provides joint membership in DFI and DFI of India and the added benefit of a local DFI presence. The chapter’s mission is to support the Indian foundation industry on a continuous and sustained basis in measured and measurable steps, to improve professionalism in the Indian foundation industry, and to embrace new technologies for faster development of India.