EFFECT OF SOIL DENSITY AND PLUG CHARACTERISTICS ON BEHAVIOR OF SINGLE PIPE PILE EMBEDDED IN COHESIONLESS SOIL AND SUBJECTED TO UPLIFT FORCE

It is a significant issue to analyze and understand the pile’s behavior as well as to predict the piles’ capacity exposed to uplifting load when designing a foundation. Experimental model tests have been conducted for a single pile embedded in cohesionless soil and subjected to uplift force. The experimental tests were performed using open-ended steel pipe piles with circular cross-sectional area an outer diameter of 50 mm in steel soil box (0.5*0.5) with four different height (0.30, 0.50 and two with 0.40 m). The tested piles have been embedment with penetration ratios (PR=L/D) of 10. Three different densities (25%, 50% and 75%) have been used to perform the tests. In addition three tests have been made with relative density of 50% to investigate the function the developed soil column inside the pile (soil plug) during installation. The results revealed that the behavior of single piles depends mainly on soil density and the ultimate pull-out capacity of the pile increases with the increasing of the soil relative density and used the data from this tests to presented formula to estimate the IFR and takes the soil state parameter as a qualitative variable. The results showed also that the removing of plugging soil decreases the pile’s pull-out capacity by about 85%. Whilst, using of closed-end or filled with concrete give higher capacity than that of open-end pipe pile by about 33% and 87% respectively.