Field Study of Shaft Resistance of Continuous Flight Auger Pile in Residual Soil Using Fiber Optic Sensing Technique

Towards a better practice of the continuous flight auger (CFA) pile in Southeast China, a field study was carried in Huangpu District of Guangzhou to examine the shaft resistance response of the CFA pile in the residual soils. For this purpose, the ultra-weak fiber Bragg gratings (FBG) were mounted to the steel cage of the pile to directly measure the shaft resistance. Two frictional and two end-bearing CFA piles were examined using the static load test. For the frictional CFA pile, the shaft resistance in the residual soil was measured as 130 kPa, much greater than the empirical one as 80 kPa. For the end-bearing pile, the measured shaft resistance in the residual soil was lower than the empirical one instead, as the deformation along the soil-pile interface cannot be fully developed under loading.