SHAFT RESISTANCE MECHANISM FOR PILES CLOSE TO BACKFILLED SAND AND ITS EVALUATION

Abstract

In this paper, compressive loading tests of a pile overlapping backfilled soil of different densities in a part of the surrounding soil were conducted to quantify the shaft resistance of the pile and the shear failure behavior of the soil adjacent to the pile. In particular, several layers of colored sand were placed in the model soil to focus on the location of shear failure in the soil near the pile. The thickness of the shear band that contributed to the shaft resistance of the pile was investigated based on the deformation of the colored sand layer observed after the loading test. In addition, a method for evaluating the increase in horizontal earth pressure due to the settlement of the pile based on cavity expansion theory was investigated. A calculation method for pile shaft resistance that considers backfilled soil was developed. The validity of the calculation method was confirmed through a comparison with experimental results.