Effect of Fines on Behavior of Braced Excavation in Sand: Experimental and Numerical Study

Abstract

In this paper, the effect of fine content in the retained sandy soil on the behavior of braced excavation has been studied using experimental and numerical models in terms of four design factors: strut force, bending moment developed in the wall, lateral deflection of the wall, and vertical displacement of the ground surface. In the experiments, the fine content of the soil has been estimated as 0, 5, and 10% (by weight). However, the numerical study has been conducted for different fine contents varying from 0 to 50% (by weight). The parametric study with 20 m depth of retaining wall; position of struts at 2, 7, 12, and 17 m below ground level; wall thickness and embedment depth as 6 and 80% of depth of excavation; and stiffness of support members as 5×105kN/m/m confirms that the values of the four design factors (strut force, wall moment, lateral wall defection, ground deflection, and net earth pressure acting on the wall) increase with the increase in fine content in the retained soil. It is also observed that predominant ground surface displacement gradually shifts from heaving to settlement as the fine content in the retained soil increases.