Observation of soil-structure interaction in double sheet pile method using X-ray CT

Abstract

A new earth retaining method, head-fixed double sheet pile method, is being developed to rationalize open-cut construction. To clarify the behavior of the soil between two sheet piles (‘inner soil’), which is important for studying the reinforcement effect of this method, model experiments were conducted with an X-ray CT system to study the interaction between the sheet pile and the inner soil. In one case, a model sheet pile fabricated using polycarbonate without sand attachment was used, while two cases with increased friction between the sheet pile and the inner soil were compared. Low frictions led to shear failure at the boundary between the sheet pile and the inner soil. In contrast, high surface friction between the sheet pile and the inner soil led to shear failure in the inner soil. This indicates that the reinforcement mechanism of this structure changes with the conditions of soil-structure interaction between the sheet pile and the inner soil. Thus, it is important to provide sufficient friction between the sheet pile and the inner soil to improve the effective reinforcement of the inner soil. This study indicates that soil-structure interaction is an important parameter for establishing a rational design for this method.