Abstract Using self-developed model drilling rig and pile model test system,a new type of soil displacement screw(SDS) pile in homogeneous sand has been studied to explore the load transfer mechanism and load deformation behaviors of full displacement pile. The investigations show that the skin friction along SDS pile is asynchronous distribution,within the soil-pile relative displacement of 20% pile diameter,the skin friction of pile due to soil-pile relative displacement is monotonous increase;and the shaft resistance of pile is much higher than the base resistance. Comparison of test results between SDS piles and continuous flight auger(CFA) piles,the factor of pile length played a more active role on the bearing capacity and deformation behavior of SDS piles than those of CFA piles. Under same model test conditions of the length,diameter of piles and soil,the ultimate bearing capacities of SDS piles are about 25% to 70% higher than those of CFA piles. Based on Terzaghi and Peck?s theory of earth pressure and the stress path method as well,the main reasons are clarified about the difference of load deformation behavior resulted from disparate pile construction methods and installation effects which lead to change physical state and mechanical parameters of soil around SDS piles and CFA piles .
|
Received: 17 June 2010
|
|
|
|