Authors: Mills, KW; Selmo, D; Todd, JB; Puller, JW; Nemcik, JA; Simonovski, Z


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Mills, KW, Selmo, D, Todd, JB, Puller, JW, Nemcik, JA & Simonovski, Z 2015, 'Experience of using the ANZI strain cell for stress change monitoring', in PM Dight (ed.), FMGM 2015: Proceedings of the Ninth Symposium on Field Measurements in Geomechanics, Australian Centre for Geomechanics, Perth, pp. 589-600,

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This paper describes the ANZI (Australia New Zealand Inflatable) strain cell and some examples of its application for stress change monitoring. The instrument has been used over the past three decades to measure three-dimensional in situ stresses using the overcoring method of stress relief and monitor three-dimensional stress changes in a range of applications mainly associated with underground coal mining, but also with civil and metalliferous mining projects. The ANZI strain cell has a pressuremeter design that allows 18 electrical resistance strain gauges at various orientations to be pressure bonded directly to the rock on a borehole wall. The instrument’s soft polyurethane membrane and hollow pressuremeter design have characteristics that facilitate deployment, enhance data gathering, and simplify analysis. Further recent developments that improve deployment and monitoring have increased the capability of the instrument. Automatic, remote, and high speed monitoring at resolutions of just a few microstrain has significantly improved the capability to measure and thereby understand the nature of changes in the three-dimensional stress in rock strata around excavations in rock.

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