Effect of surface roughness on uplift capacity of piles embedded in sandy soil

The uplift load value of a single pile depends mostly on the skin friction resistance resulting from the interaction between the pile surface and the soil surrounding the pile. It is known that the magnitude or severity of this resistance that occurs between the pile and the soil surrounding it depends on different parameters such as pile surface roughness, soil density, and pile embedment ratio. Therefore, in the present study, the effect of pile surface roughness on the uplift behaviour of piles embedded in cohesionless soil is investigated both experimentally and numerically. In the tests, the effects of parameters such as soil density, surcharge load and pile placement method on the uplift capacity are also investigated. In addition, the data obtained from the tests are compared with the data produced by the finite element method, and the performance of the numerical model considered within the scope of the study is evaluated. While it is seen that the experimental and numerical results are quite compatible, a significant increase in pile uplift capacity is observed with the increase of soil density and pile surface roughness. Besides, the test results showed that some pile surface roughness values (Rn=0, 0.04, and 0.10) are critical in determining the uplift behaviour of the pile, while the surcharge load and pile placement method play an important role in increasing the pile uplift capacity.