Nishio, A, Zhang, H, Akutagawa, S, Takeya, K, Ishizuka, Y & Katayama, T 2013, 'Visualisation of deformation or force in rock supporting structures', in Y Potvin & B Brady (eds), Ground Support 2013: Proceedings of the Seventh International Symposium on Ground Support in Mining and Underground Construction, Australian Centre for Geomechanics, Perth, pp. 657-666, https://doi.org/10.36487/ACG_rep/1304_46_Akutagawa
(https://papers.acg.uwa.edu.au/p/1304_46_Akutagawa/)
Abstract: New sensors have been developed for simultaneous monitoring and visualisation of risk conditions for mining applications to achieve an advanced safety management scheme using ‘colour of light’ as a key technology of the proposed method. These sensors are designed and built based on the new monitoring concept called onsite visualisation. They are capable of: 1) sensing data; and 2) visually outputting the measurement results simultaneously by using Light Emitting Diode (LED) for workers. In this paper two new methods for visualising deformation or force in rock supporting structures, such as rockbolts or ground anchors are reviewed. Firstly a colour of light is used as the principal indicator of deformation or force in the rockbolt or ground anchor. An additional set of stiff cable and spring is used along with rockbolt or ground anchor so that the deformation can be easily measured. The measured deformation can then be translated into colour of light using a colour-filter switch. The use of this method is suited to underground spaces for ease in visual identification. Secondly, the number of plastic optical fibres receiving sunlight becomes the principal indicator of deformation or force in rock supporting structure. A specially designed mechanical switch is set on a ground anchor head. As the force changes the tendon changes its length, which then is transferred to the shift of light blocking the metal shield panel. When the shield panel moves the number of plastic optical fibres receiving sunlight changes, from which approximate values of the anchor force can be identified. Once this sensor is set, long term observation of anchor forces (limited to observation during daytime only) becomes possible without using electricity. Some experiences in using these new tools are presented and their potential in mining applications are discussed.