An Experimental Investigation on Interference of Piled Rafts in Soft Soil

Abstract

By using small scale model tests, the interference effect on the vertical load-deformation behavior of a number of equally spaced rafts and piled rafts, placed in the artificially consolidated soft clay was investigated. The effect of spacing (s) among foundations on the results was explored. A new experimental setup was proposed in which uniform load was applied by using steel beam of adequate flexural strength and ball bearings to transfer the vertical load equally on both the foundations. The bearing capacity decreases continuously with decrease in spacing among the foundations. The interference effect becomes further prominent with piled raft foundation. In contrast to decrease in the bearing capacity, with decrease in spacing of foundations, an increase in the foundations settlement associated with the ultimate state of shear failure was observed. The present experimental observations were compared to the results obtained by using PLAXIS. The results of this laboratory investigation will be helpful in finding the minimum spacing between the rafts and piled raft foundation for better performance.

Keywords: Piled raft; Model test; soft clay; Interference effect; spacing; PLAXIS