Study On Bearing Characteristics Of Explosive Expansion Steel Piles

The belled pile has been widely used both at home and abroad, and has a variety of pile types. In this paper, a new pile type, explosive expansion steel pile, is proposed on the basis of an new patent about the explosive expansion devices. The basic configuration of explosive expansion steel pile is a steel pile. It form a explosive expansion ball through the expansion of explosive expansion devices in the construction site,serving as another source of bearing capacity in addition to the side friction. In such a way, it improves the load transfer mechanism, increases the carrying capacity of the pile, and reduces the deformation of the pile and soil. ABAQUS finite element software has been widely applied in geotechnical engineering, and has strong functions in solving the nonlinear problem; It provides contact analysis model, and can effectively simulate the separation and slip in the interface between the pile and soil, etc. through the ABAQUS finite element analysis software, contact analysis model of the pile and soil is established to analyze the load transfer mechanism and bearing properties of the explosive expansion steel pile under the vertical and horizontal load; and get the comparative analysis about the influence of the parameters such as the diameter, location and quantity of explosive expansion ball on the bearing capacity of explosive expansion steel pile, and highlight its advantage about the bearing capacity.The results show that:(1) under vertical load on the top of the explosive expansion steel pile, there are two stress diffusion path between the pile and soil: the first one is pile side friction, namely the friction role in contact interface between pile and soil; the second one is positive pressure between pile and soil around the explosive expansion ball. In the early stages of loading, the displacement of piles is small, the first stress diffusion path occupied the main position, but as loading continual, the displacement of piles increases, and the positive pressure between pile and soil around the explosive expansion ball is gradually improved to the control position in the end. (2) under the horizontal load, different external load point position will lead to three different deformation damage. (3) the diameter of explosive expansion ball has a great influence on the bearing capacity of the explosive expansion steel pile. The greater diameter of the explosive expansion ball, the greater bearing capacity of the explosive expansion steel pile is. The position of explosive expansion ball also has a great influence on the bearing capacity of the explosive expansion steel pile, as the position lower, the bearing capacity of the pile is greater. The quantity of the explosion expanding ball also is one of the factors that have impact on the bearing capacity of pile, in general, the more quantity of the explosive expansion ball, the bearing capacity of explosive expansion steel pile is higher.