Matteo Fiorucci

Multi-sensor system designed for monitoring rock falls: the experimental test-site of Acuto (Italy)

This paper illustrates the design of a multi-sensor monitoring system located in Acuto (Frosinone - Central Italy) where an abandoned quarry was devoted to experimental test-site. The test-site is managed by the Research Centre for the Geological Risks (CERI) and is focused on testing and comparing multi-sensing and multi-parametric remote techniques for early warning, applied to rock falls with strategic infrastructure targets. The final aim of this testing is to process the data collected by techniques integrated by a network of conventional and smart sensors, following observational-bases and statistical approaches. The installed multi-sensor monitoring system consists in 2 control units for weather monitoring, 1 thermometer for the rocky mass temperature, 10 strain-gauges for rock mass joints, 2 optical devices (Smart Cameras) and 1 nanoseismic monitoring network.

Thermal Response of Jointed Rock Masses Inferred from Infrared Thermographic Surveying (Acuto Test-Site, Italy)

The Mediterranean region is affected by considerable daily and seasonal temperature variations due to intense solar radiation. In mid-seasons, thermal excursions can exceed tens of degrees thus influencing the long-term behaviour of jointed rock masses acting as a preparatory factor for rock slope instabilities. In order to evaluate the thermal response of a densely jointed rock-block, monitoring has been in operation since 2016 by direct and remote sensing techniques in an abandoned quarry in Acuto (central Italy). Monthly InfraRed Thermographic (IRT) surveys were carried out on its exposed faces and along sections of interest across monitored main joints. The results highlight the daily and seasonal cyclical behaviour, constraining amplitudes and rates of heating and cooling phases. The temperature time-series revealed the effect of sun radiation and exposure on thermal response of the rock-block, which mainly depends on the seasonal conditions. The influence of opened joints in the heat propagation is revealed by the differential heating experienced across it, which was verified under 1D and 2D analysis. IRT has proved to be a valid monitoring technique in supporting traditional approaches, for the definition of the surficial temperature distribution on rock masses or stone building materials.

Rock Falls Impacting Railway Tracks: Detection Analysis through an Artificial Intelligence Camera Prototype

During the last few years, several approaches have been proposed to improve early warning systems for managing geological risk due to landslides, where important infrastructures (such as railways, highways, pipelines, and aqueducts) are exposed elements. In this regard, an Artificial intelligence Camera Prototype (AiCP) for real-time monitoring has been integrated in a multisensor monitoring system devoted to rock fall detection. An abandoned limestone quarry was chosen at Acuto (central Italy) as test-site for verifying the reliability of the integrated monitoring system. A portion of jointed rock mass, with dimensions suitable for optical monitoring, was instrumented by extensometers. One meter of railway track was used as a target for fallen blocks and a weather station was installed nearby. Main goals of the test were (i) evaluating the reliability of the AiCP and (ii) detecting rock blocks that reach the railway track by the AiCP. At this aim, several experiments were carried out by throwing rock blocks over the railway track. During these experiments, the AiCP detected the blocks and automatically transmitted an alarm signal.

3D Remote survey of a rock wall hosting a multi-sensor monitoring system in a test-site (Acuto, Italy)

A multi-sensor monitoring system was installed in an abandoned quarry at Acuto (Frosinone - Central Italy) to test multi-sensing and multi-parametric remote techniques for early warning incase of rock failures threating strategic infrastructures. The multisensory monitoring system consist in: i) a meteo-climatic system, including a conventional weather stations and an innovative TSA-BOXone; ii) a geotechnical system, including thermometer for the rock mass temperature, strain-gauges for micro-fractures of rock mass, extensometers on open joints for detecting stress-strain conditions; iii) a nanoseismic monitoring system was also temporary installed to detect low magnitude vibrations to be regarded as precursors of rock failures. To correctly design the multi-parametric monitoring system, the rock wall was scanned to identify the main joint sets.Three GPS monographs were preliminary obtained in order to spatially geocoding the rock wall. From November 2015 to May 2016 remote scanning surveys were carried out on the quarry face by two different approaches: i) topographic 3D survey by Leica Total Station; ii) optical survey by 3D photos technique analyzed by Structure from Motion technique. The topographic survey provided high definition geocoded point clouds. These outputs were compared with the ones obtained by the SFM technique on 3D photos to test their reliability. At this aim, a Gaussian bi-modal distribution of the surveyed distances was obtained from each measurement; the comparison among the so derived distributions demonstrates that the computed errors are negligible and the main differences result at the boundaries of the sampled 3D domain. This comparison encourages the use of the photography technology by SfM technique to obtain multi-temporal geocoded point clouds for change detection analyses to point out evidences of scar zones due to slope failures. Thisapproach guarantees a very quick and accurate practice with easy management hardware and low software costs.

Experiment of an innovative nanoseismic monitoring applied to gravity-induced slope instabilities in a karstified rock mass

The Peschiera Springs slope (RI), which hosts the drainage plant of the Romes aqueduct, is affected by a gravitational slope deformation process, that is responsible for a rock-mass lateral spreading, associated to several landforms including sinkholes, subvertical scarps and trenches. An experiment, based on an innovative method of monitoring, was carried out to record microseismic events generated by underground instabilities such as failures and collapses. At this aim a SNS (Seismic Navigation System) array was installed during the year 2013 inside a the tunnel of the drainage plant in order to carry out a continuous monitoring. The nanoseismic monitoring, allowed to record 37 microseismic events. The seismic records were managed by NanoseismicSuite software that allowed to identify and characterize two different typologies of events: 19 underground collapses and 18 underground failures. The locations of these events are in good agreement with the evolutionary geological model of the ongoing gravitational slope deformation, i.e. with the spatial distribution of the main trenches and scarps on the slope.