Research on analytical conversion method of self-balanced test pile results

Abstract

An analytical conversion method of self-balanced test of foundation pile bearing capacity is proposed. First, the load transfer matrices for the elastic-plastic state of the upper and lower segment piles in a multi-layer foundation were derived under the assumption of the load transfer function of the pile side associated with the ideal elastic-plastic model. Then the internal forces and vertical displacements at each micro-element of the upper and lower segment of the pile were calculated by programming, and the results of the self-balanced test pile were converted into the load-displacement curve of the conventional static load test by substituting the accurate conversion formula, and the ultimate bearing capacity was obtained. Finally, by combining with an engineering test pile example, two groups of loading results of anchor pile method and self-balanced method were used to verify the theoretical analysis of conversion method in this work. It can be concluded that the load-displacement curves obtained by this conversion method are more consistent with the results of the conventional static pressure tests compared with the simplified conversion method. Moreover, the proposed model can be widely used in the self-balanced test engineering of pile bearing strength with sufficient accuracy.