Soil Arching Effect Associated with Ground Movement and Stress Transfer Adjacent to Braced Excavation in Clayey Ground

Abstract

A field test for investigating the soil arching effect behind the diaphragm wall was carried out in an average 17-meter-deep, braced excavation in the normally-consolidated clayey ground. Horizontal and vertical ground movements, lateral earth pressures, diaphragm wall deformations, and strut loads were measured and analyzed. The soil arching zone and the loosened zone behind the wall are determined by the force and displacement boundary conditions of soil mass. The arching stress transferred along the arching zone drags the soil against the bracing and increases the lateral earth pressure around the upper parts of the wall. This results in a passive state of stress and horizontal compression and vertical extension of the soil around the crest of the wall. The top of the arching zone extends vertically and is on the same vertical line as the maximum ground surface settlement. The three-dimensional arching is essentially formed by the superposition of multiple transverse two-dimensional archings along the longitudinal direction of excavation, of which two arching feet were located near the corner.