sensors Article Advances on Measuring Deep-Seated Ground Deformations Using Robotized Inclinometer System Paolo Allasia , Danilo Godone * , Daniele Giordan , Diego Guenzi and Giorgio Lollino Italian National Research Council, Research Institute for Hydrogeological Prevention and Protection, Geohazard Monitoring Group (GMG) Strada delle Cacce, 73, 10135 Torino, Italy; paolo.allasia@irpi.cnr.it (P.A.); daniele.giordan@irpi.cnr.it (D.G.); diego.guenzi@irpi.cnr.it (D.G.); giorgio.lollino@irpi.cnr.it (G.L.) * Correspondence: danilo.godone@irpi.cnr.it; Tel.: +39-011-3977-832 Received: 6 June 2020; Accepted: 2 July 2020; Published: 5 July 2020   Abstract: In the field of geo-hazards and geo-engineering, monitoring networks represent a key element for the geological risk assessment and the design and management of large infrastructures construction. In the last decade, we have observed a strong development on remote sensing techniques but just small changes in the subsoil observations. However, this type of measurement is very important to have a three-dimensional representation of the studied area, since the surface measurements often represent a sum of deformations that develop in a complex way in the subsoil. In this paper, we present a robotic inclinometer system developed to acquire deep-seated ground deformations in boreholes. This instrumentation combines advantages offered by manual inclinometer measurements with a robotized approach that improves the results in term of accuracy, revisiting time, and site accessibility. The Automated Inclinometer System (AIS) allows one to explore automatically all the length of the monitored borehole using just one inclinometer probe with a semi-wireless system. The paper presents the system and a detailed dataset of measurements acquired on three inclinometer tubes installed for the monitoring of the construction phase of the new Line C Metro of Rome. The dataset was acquired in real monitored site and undisturbed conditions and can represent a benchmark for modern inclinometer measurements. Keywords: inclinometer; landslides; monitoring systems; subsoil observation; geo-engineering 1. Introduction The monitoring of soil and subsoil deformation phenomena plays an important role in the fields of earth sciences and engineering-geology. Currently available instruments and techniques allow one to track the evolution of geo-hydrological events and the construction of large infrastructure with high accuracy and temporal resolution. In the last decade, a huge development in the methodologies to measure ground deformation was observed. On the contrary, at the same time, only a reduced increase in the field of subsoil deformation measurement techniques was recorded. This difference is mainly related to the significant development in the field of remote sensing and its possibility to observe large areas in ever-shorter times [1–4]. However, the deformation measured at the ground level represents a sum of what happens in the subsoil. In many cases, in order to explain the real mechanism that caused the surficial deformation measured, a series of hypotheses is needed. In this context, the measurement of subsoil deformations represents an important source of information for a more correct and more complete interpretation of the phenomenon in terms of thickness of soil involved and vertical distribution of stress and resistant forces. Despite the importance of these parameters, in the last decade, the methods and instrumentation to measure subsoil deformations are quite unchanged [5–15]. The main technique used is the measurement of inclination over the time in specific boreholes (i.e., inclinometers). The observed phenomena (landslides, geotechnical works, Sensors 2020, 20, 3769; doi:10.3390/s20133769 www.mdpi.com/journal/sensors