Proceedings of DFI-India 2019: 9th Conference on Deep Foundation Technologies for Infrastructure Development in India, (DFI)
Installation of Large Diameter Bored Pile Socketed in Hard Rock with RCD for MTHL, Mumbai
Akshay Sakhuja, Vignesh R., and Inki Choi
One of the recent developments that has been carried out in Indian construction industry for deep foundation is the use of reverse circulatory drilling popularly known as RCD for large diameter bored piles. RCD is preferred to be used for large-diameter piles, deep depth, hard rock drilling and bored piling in marine condition, because its operation is faster compared to other conventional drilling and easier to clean the bore hole. The fluid and cuttings flow up the drill pipe and down the annulus. In softer formations, this causes less washout and makes sampling faster, the process is known as airlifting. Conversely, for the installation purpose of the machine, it requires tubular casing or commonly known as pile liner of sufficient thickness and the RCD is mounted upon the liner and this liner needs to suffice the additional load of the RCD rig and works as top down drilling. The liner is generally embedded with help of vibro-hammer, oscillator / pre boring up to the rock level and then impact hammer may be used to terminated half to 1 meters in the rock depending upon the qualitative nature of the rocks i.e. weathering, RQD, strength of rock etc. The present study has been carried out for “Mumbai Trans Harbor link package 01” or popularly known as MTHL Bridge, the longest sea crossing bridge in India once completed. The above said project is being construed by L&T construction for MMRDA across Mumbai bay between Sewri on Mumbai side and Chirle on the Navi Mumbai side in Maharashtra India. For this project, various large dimeter piles are socketed into hard rock with the help of RCD and conventional drilling, and it is the case study on RCD drilling i.e., premature refusal of liner or over driving of liner, sinking of liner, drilling issues faced on using RCD, along with advantages of RCD vs conventional drilling in hard rock in Mumbai region.
|article #3288; publication #1059 (India2019)|