Study on the Force Model of Squeezed Branch Piles Based on Surface Potential Characteristics

Abstract

Squeezed branch piles, which boast the advantages of great bearing capacity, small settlement, and good stability, are an important infrastructure in the foundation of buildings, and their safety state is related to the safety of the entire structure. As a non-destructive testing method, surface potential can be used to effectively evaluate the damaged state of a pile foundation without destroying its stability. On this basis, in this study, the characteristics of surface potential change during settlement and deformation of squeezed branch piles under graded loading were tested and analyzed with the aid of a self-made loading system of reaction beams and an LB-IV multi-channel potential data acquisition system. The results show that: Under graded loading, squeezed branch piles can produce surface potential signals whose intensity can well reflect the settlement and local failure characteristics of the pile foundation; The potential signals change in advance of load; and they fluctuate violently before local fracturing of squeezed branch piles. The unstable fluctuation of the potential signal can be regarded as a precursor to the fracturing of squeezed branch piles. The research results have positive theoretical significance and important application value for assessing the stability of both branch piles and their stress states on site and monitoring and forecasting the disaster of pile foundation instability.

Keywords

• graded loading
• squeezed branch piles
• surface potential
• precursor feature
• force model