ISSN: 0149-6115
Page Count: 8

A Miniature Soil Inclusion for Measuring Axial Force and Radial Stress

Standing, JR
Lecturer,Cambridge University,

Burland, JB
Professor of Soil Mechanics,Imperial College of Science, Technology and Medicine,

(Received 2 March 1999; accepted 25 May 2001)

Abstract

This paper describes the design, development, and manufacture of a miniature soil inclusion 175 mm long and 8 mm in diameter for measuring axial force and radial stress at three points along its length. The individual devices rely on strain gages for their operation and were found to be stable in a laboratory environment. The axial force and radial stress measurements can be resolved to less than 1 N and 1 kPa, respectively. The model inclusion has been used in a study to investigate the development of shear stress along a soil nail. The instrumentation allowed the influence of arching to be positively identified. The paper includes discussion of factors such as calibrating for cross-effects, converting the electrical outputs to engineering units, and cell-action effects. These factors along with the soil stiffness govern the accuracy of measurement.

Keywords:
instrumentation, soil inclusion, laboratory model testing, radial stress and axial force cells, cross-effects, cell-action effects

Paper ID: GTJ11076J
DOI: 10.1520/GTJ11076J
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