Multisensor monitoring for detecting rock wall instabilities from precursors to failures. The Acuto test-site (Central Italy)

This paper presents the multisensor monitoring system operating since 2016 at the Acuto quarry test-site (Central Italy) with the aim to understand how natural and anthropic conditioning factors lead a fractured rock mass to failure. This monitoring system is composed of: i) weather station; ii) rock thermometer; iii) strain devices (both strain-gages and extensometers); iv) an Artificial intelligence optical Camera Prototype –AiCP–; v) InfraRed Thermal Camera; vi) microseismic array. Data analysis carried out following different approaches (e.g. physically based as well as statistic methods) on the Acuto dataset recorded so far, allowed to establish cause-to-effect relations among forcing actions and induced strain effects, highlighting the main role of the thermal forcing on rock mass deformations both on daily and seasonal thermal cycles. Microvibrational emissions of the rock mass forced by natural triggering and preparatory processes, such as the ones related to the action of thermal cycles, were also detected by microaccelerometers and interpreted as precursor signals of rock failure events. The latter events can be registered and detected by means of optical monitoring systems if they occur. Therefore, thermomechanical effects and microseismicity of the outcropping rock mass at the Acuto quarry were analysed through monitoring techniques in natural conditions and implementing numerical modelling. Since 2018 the Acuto quarry is an official test-site funded by the Italian Ministry of Education, University and Research. The here presented monitoring system will be improved and expanded in the following years with a view to testing new technological devices for a comprehensive stress-strain and thermal monitoring.