Critical Buckling Load Calculation of Piles Based on Cusp Catastrophe Theory

Abstract

Buckling instability of piles can be categorized as a catastrophe failure so the catastrophe theory can be used for the analysis of buckling stability. Therefore, the cusp catastrophe theory was applied to calculate the critical load for pile buckling damage. The calculation width problem for a pile was analyzed. The effect of upper structure load on pile buckling was considered. Rankine's active and passive earth pressure coefficients were employed in simulating the side forces on the pile shaft. Based on the above, two cusp catastrophe models of the critical buckling load were proposed for a top-free bottom-fixed pile and a top-hinged bottom-hinged pile, respectively. Principles for selecting the cusp catastrophe models were also suggested. In order to take into account the difference between the practical and the assumed lateral earth pressure distribution, a coefficient ξ of values of 0.75 ∼ 1.0 was recommended to correct the calculated critical buckling load. According to the field testing results of small-diameter TC piles (Plastic tube Cast-in-Place Concrete Pile) with a diameter of 16 cm, the model for top-hinged and bottom-hinged piles was selected for comparative analysis. The calculated and test results show good agreement and the correction factor value was discussed.

Keywords:

• Buckling damage
• critical buckling load
• cusp catastrophe theory
• pile