Laboratory Study of the Effect of Pile Surface Roughness on the Response of Soil and Non-Displacement Piles

This paper presents the results of axial load tests performed on instrumented model piles with different surface roughnesses. The model piles were pre-installed in a large-scale, half-circular chamber with a viewing window in its flat-side wall. Uniform silica sand samples in dense and medium dense states were prepared using dry pluviation. Digital image correlation technique (DIC) was used to study the effects of pile surface roughness and soil density on the response of the soil during loading of the model piles. Test results show that the extent of the zone next to the pile that is affected by loading of the pile increases as the pile surface roughness and soil density increase. The development of a shear band next to the pile shaft was also studied by carefully analyzing images taken with a digital microscope during loading of the model piles. Furthermore, the shaft resistances of the loaded piles were measured during the loading tests to investigate the effect of soil density and surface roughness on the response of the model piles.