Field test research on distribution characteristics of internal force for cantilever retaining piles

Through the measured internal force of the retaining pile for the deep excavation in Xining railway station,behavior and changing pattern of internal force are studied under different conditions. The test results suggested that the measured reinforcement stress of cantilever retaining piles should be less than designed value. There is obviously synergy between the capping beam and the retaining piles,which makes the behavior of the retaining piles under lateral pressure is quite different from that of the upright free head shaft. The behavior of retaining piles can't be improved though deepening the embedded depth of the retaining piles. The measured maximum moment of the retaining piles lie in the area between the foundation pit bottom and over 1. 5 m,and its value is less than the theoretical value. This test results can provide reliable basis for the design of cantilever retaining piles.