Title: Rockfall precursor detection based on rock fracturing monitoring by means of optical fibre sensors

Authors: Luca Schenato; Luca Palmieri; Elena Autizi; Fabio Calzavara; Leonardo Vianello; Giordano Teza; Gianluca Marcato; Raffaele Sassi; Alessandro Pasuto; Antonio Galgaro; Andrea Galtarossa

Addresses: Research Institute for Geo-Hydrological Protection, National Research Council, Corso Stati Uniti, 4, I-35127, Padova, Italy ' Department of Information Engineering, University of Padova, Via Gradenigo 6/B, I-35131, Padova, Italy ' Department of Information Engineering, University of Padova, Via Gradenigo 6/B, I-35131, Padova, Italy ' Department of Information Engineering, University of Padova, Via Gradenigo 6/B, I-35131, Padova, Italy ' Department of Information Engineering, University of Padova, Via Gradenigo 6/B, I-35131, Padova, Italy ' Department of Geosciences, University of Padova, Via Gradenigo, 6/A, I-35131, Padova, Italy ' Research Institute for Geo-Hydrological Protection, National Research Council, Corso Stati Uniti, 4, I-35127, Padova, Italy ' Department of Geosciences, University of Padova, Via Gradenigo, 6/A, I-35131, Padova, Italy ' Research Institute for Geo-Hydrological Protection, National Research Council, Corso Stati Uniti, 4, I-35127, Padova, Italy ' Department of Geosciences, University of Padova, Via Gradenigo, 6/A, I-35131, Padova, Italy ' Department of Information Engineering, University of Padova, Via Gradenigo 6/B, 35131 Padova, Italy; International Institute for Urban Systems Engineering, Southeast University, Nanjing, China

Abstract: The monitoring of the acoustic emissions (AEs) due to rock fracturing allows the detection of the rockfall precursor signals, leading to a strong improvement of the real time assessment of the induced risk. A network of piezoelectric sensors (PZTs) provides reliable AE data, as testified by a series of applications in non-destructive testing, but PZTs are strongly affected by lightings and electromagnetic interference. In order to avoid such PZT drawbacks and limitations and therefore to allow the rock fracturing monitoring in unstable slopes, two FOS architectures (referred to as fibre coil sensor and ferrule top cantilever) have been recently proposed in previous works from the same authors. In this paper, the two sensors are tested in a more realistic scenario, by monitoring AE in a rock block in which crack is induced by highly expansive mortar; complementary activities, mainly aimed at the recognition of the type of expected signals and optimisation of the sensor array in the framework of the monitoring system, are also described here.

Keywords: rockfall precursor signals; rock fracturing; acoustic emission; PZT; piezoelectric sensors; fibre optic sensors; risk assessment; rock fracture monitoring; unstable slopes; rockfalls.

DOI: 10.1504/IJSMSS.2013.056482

International Journal of Sustainable Materials and Structural Systems, 2013 Vol.1 No.2, pp.123 - 141

Available online: 20 Sep 2013 *

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