Some Experiences with Drilled Shaft Construction in Punjab Alluvium, Using Different Drilling Methods

It is widely known to the piling engineers that use of different drilling techniques has different impact on the construction of bored piles/drilled shafts. However, the comparative effects of various drilling methods on the allowable load-carrying capacity of drilled shafts have not been widely substantiated in quantitative terms in Pakistan. In Pakistan, a host of pile boring methods are in vogue, depending mainly on the ground conditions at the construction site. In Punjab, thick alluvium is present mostly all over, in the form of their cover of cohesive soils of variable thickness over sands. Recently, novel bored piling and their load testing experiences have been obtained during the construction of thousands of large diameters drilled shafts for Lahore Metro Orange Line Train Project, Rapid Bus Transit Project, RLNG Thermal Power Plants at Bhikki and Balloki, etc. This paper gives an account of the shaft construction in Punjab alluvium using various techniques and the resulting impact on the allowable load-carrying capacity of shaft. The findings of this paper are considered very important as well as relevant to the bored pile design and construction engineers, who will develop a better insight in the piling activities in similar conditions.