Embedded cantilever retaining walls in sand

• Published in: Géotechnique Vol. 60; no. 11; pp. 813 - 823
• Main Authors: LI, A. Z, LEHANE, B. M
• Format: Journal Article
• Language: English
• Published: London Telford 01.11.2010; ICE Publishing
• Subjects: Earth sciences; Earth, ocean, space; Engineering and environment geology. Geothermics; Engineering geology; Exact sciences and technology; Retaining walls; strain; experimental studies; stress; models; shear; strength; creep; excavations; back analysis; retaining walls; finite element analysis; stiffness; sands; earth pressure; sand; instruments; displacements; case history; piles; particles; soils
• ISSN: 0016-8505; 1751-7656
• DOI: 10.1680/geot.8.P.147

This paper describes a case history involving staged excavation adjacent to an instrumented cantilever bored pile contiguous wall in sand. The instrumentation enabled reliable estimates to be made of the variation of pile bending moments from which observations are made related to the development of lateral earth pressures. Particle image velocimetry was employed to obtain a unique dataset of lateral and vertical displacement measurements behind the wall, which may be used to evaluate existing predictive approaches for assessment of excavation-induced movements. Simple finite-element back-analyses of the experiment, employing a linear elastic Mohr–Coulomb soil model, showed that measured wall displacements and moments could be predicted using expected effective stress strength parameters, but that best-fit equivalent linear operational stiffnesses were well below those commonly assumed in practice. Creep is shown to have a critical effect on the displacements of the wall and behind the wall and needs to be incorporated in any realistic predictive approach.