Axial force coherence study of strut loading in soft soil deep excavation

Abstract

The coherence of the axial force between steel struts during excavation, i.e. the axial force coherence, is a critical factor affecting axial force control. This study introduces a novel method for calculating the horizontal displacement of a diaphragm wall, applicable to servo-controlled excavation, based on the non-limit earth pressure theory. Furthermore, the study investigates the coherence of axial forces in prestressed struts. First, the diaphragm wall is modeled as a rectangular thin plate with two opposite edges simply supported and the other two edges free. It is then divided into $m\times n$ small rectangles along the depth and length directions, and the external combined force within each small rectangle is calculated. Secondly, a non-linear set of force–displacement equations is constructed, and the recursive equation of the displacement of the diaphragm wall is obtained by applying the Newton–Raphson method. The method’s accuracy is confirmed through field measurement comparisons. Subsequently, The paper then applies the proposed methodology to scrutinize the effects of loading on individual and multiple struts on the axial forces of adjacent struts. The loading scheme for struts in deep excavation within soft soil areas can be referenced by utilizing this method.