A Research on Access of Load Carrying Capacity of Large Diameter Piles

Abstract

The evaluation of load carrying capacity of piles needs the geotechnical properties, penetration tests, the nature of the subsoil both around and beneath the proposed pile, adequate description of rock to convey its physical behavior on borings, dead loads, live loads dimensions of the piles (length and diameter of pile). To compare the length and diameter response of bored cast in situ piles, the data required is obtained from the site of project name Four Laning Project of Nagpur-Saoner-Betul Section of NH-69. The subsoil profile of site shows the clayey and silty clayey soils at the top to the considerable depth underlying highly weathered sandstone. The water table is observed from 4.5 m below the ground level. Here it is not possible to provide shallow, raft foundation as the soil strata mostly clayey and silty clayey soils which have very less safe load bearing capacity. Hence deep foundation proposed for the work. Sufficient number of borings taken in accordance with IS: 1892. Study is done by using all these geotechnical engineering properties at all bore holes locations, varying length and diameters of piles for evaluation of load carrying capacities as per IS:2911 (Part 2) and IRC:78. The load carrying capacity for different diameter of piles and for different length of piles goes on increasing with the increase in diameter. The contribution of end bearing resistance increases up to 170%, whereas contribution of frictional resistance increases up to 40%. Theoretical settlement for different diameters of piles for 25m length of pile has been computed. It has been observed that the theoretical settlement for 1.2 m diameter pile for 25 m length of pile is found to be more than actual settlement obtained from pile test for the same dimensions of the pile. Since theoretical settlement prediction is within in permissible limit and greater than the settlement obtained from the actual pile load test data, the load – settlement designed using excel can be used by the geotechnical engineers for prediction of the load and settlement calculations.