City Research Online

Abstract

Shafts are frequently constructed to allow access to subsurface infrastructure and the resulting excavation is deep and relatively narrow. Shafts may be constructed using a variety of methods and plan forms dependent on ground conditions and intended use. An axisymmetric (cylindrical) geometry is often preferred due to the relatively simple structural analysis, construction method and for a number of approaches that are available to estimate the ground movements around such an excavation. In certain cases, particularly when there is restricted space both above and below surface, non-circular shafts could be a preferred solution. The assessment of surface movements around non-circular shafts is difficult as little information exists and there are few empirical prediction methods available. In this study, a series of centrifuge tests have been conducted to investigate the effects of modifying the cross-sectional profile of a shaft (i.e. circular in plan compared with elliptical). Analysis of measurements obtained from centrifuge tests undertaken at City, University of London’s geotechnical centrifuge facility are presented and compared with existing predictive methods. An addendum to the empirical equations and procedures for predicting surface settlements arising from circular shafts is presented to allow for the assessment of movements around elliptical shafts in clay.

Publication Type:	Article
Additional Information:	This is the accepted version of an article accepted for publication in International Journal of Physical Modelling in Geotechnics by ICE Publishing.
Publisher Keywords:	Shaft construction; Ground movements; Centrifuge modelling
Subjects:	T Technology > TA Engineering (General). Civil engineering (General)
Departments:	School of Science & Technology > Engineering
SWORD Depositor:	Symplectic Administrator

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