Article

Underground Landslide Displacement Monitoring: A New MMES Based Device

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Abstract

This paper describes the analysis of the effectiveness and reliability of a new type of inclinometric chain, which is still under development by the authors, and is intended to be applied in the underground slope monitoring field. In the first part, the paper describes the new instrumentation which should allow for a deeper and detailed understanding of the type, location and origin of slope movements that should, in turn, help in understanding the triggering causes and the evolution mechanisms of landslides, and provide an innovative and substantial contribution to their stability analysis and control. The second portion of the paper is dedicated to a comparison between the classic instruments and the new MUMS device, demonstrating the advantages of measurement automation and economy in the use of the proposed device, which could also be equipped with other electronic instruments that would allow the measurement of other interesting physical quantities (such as pore pressure, temperature, stresses, etc.) together with displacement components.

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... localized failure surface). Among others, a new automated device based on MEMS (Micro Electro Mechanical Systems) for displacement monitoring has been recently released (Segalini & Carini, 2013) on the market. The system, which can be installed at any inclination and is remotely controlled, is custom made for the specific installation, in order to maximize precision and accuracy of the measurement. ...
... No indication were obtained regarding the temporal distribution of displacement during the observed period, making this monitoring outcome not useful for remedial design. An automated inclinometer device (Segalini & Carini, 2013) has been installed last year and recorded data have provided a detailed description of location and temporal distribution of displacement (Fig. 5) and average velocities (Fig. 6). A first tentative definition of an early warning threshold was proposed. ...
Conference Paper
Monitoring in field performances of rock masses is required and widespread in engineering practice for both handmade structures (tunnels, cuttings, etc.) and natural sites (i.e. landslides). The presence of discontinuities and their role in displacement localization and hydrogeological anisotropy of rock mass are the key elements in order to define an appropriate monitoring program. The application of new nanotechnologies in the geotechnical and rock mechanic fields has increased the amount of acquired information both in space and frequency. Along with the awaited introduction in the EC7 of specific considerations regarding geostructural characterization and failure criteria definition, it is desirable to propose specifications regarding field instrumentation monitoring devices and data analysis. A review of the rock mass key physical properties that should/can be monitored in field, according to specific projects or aims, is presented, along with the state of the art of suitable field monitoring equipment.
... In particular, it has been recently presented (Segalini et al., 2011) a new system, called MUMS (Modular Underground Monitoring System), finalized to measuring and recording the data described above. The features of the system and its peculiarities can be found in previous publications as well as preliminary considerations about the accuracy that can be expected from the use of such systems (Segalini et al., 2011(Segalini et al., , 2013. ...
... In particular, it has been recently presented (Segalini et al., 2011) a new system, called MUMS (Modular Underground Monitoring System), finalized to measuring and recording the data described above. The features of the system and its peculiarities can be found in previous publications as well as preliminary considerations about the accuracy that can be expected from the use of such systems (Segalini et al., 2011(Segalini et al., , 2013. ...
Chapter
The paper illustrates the efficiency of a novel inclinometer device by comparing results obtained from some prototypes installed in three landslides and those derived from classic inclinometers. The new device, called Modular Underground Monitoring System (MUMS) is intended to be applied for natural and artificial slope deformation monitoring and landslides dynamics control, assessment and forecasting. The MUMS instrumentation was developed from the idea of replacing the standard measurement procedure by locating nodes at known distances along a connecting cable placed within a vertical borehole. Each node measures its local orientation (related to the National Elevation Dataset (NED)) by means of a micro electro-mechanical system (MEMS) formed by a 3D digital linear acceleration sensor and a 3D magnetic sensor. This allows us to determine the direction cosines of the borehole axis in each node and calculate its 3D shape and deformation along the whole borehole. This paper compares the classic instruments and the new MUMS device, with evidence of the advantages of measurement automation and economy in the use of the proposed device, which could also be equipped with other electronic instruments that would allow the measurement of other interesting physical quantities (i.e. pore pressure, temperature, stresses etc.) together with displacement components. The comparison is carried out through the examination of few installation in various types of landslides, with particular attention to the accuracy and repeatability of the measurements that are automatically made.
... The single-point sliding inclinometer has just a single sensing unit that slides in the inclinometer pipe and records each data point at different moments. The multi-point fixed inclinometer contains several sensing units that are statically installed in the borehole, and it measures all of the data at the same time [27]. The former is inexpensive but requires manual manipulation, and later maintenance costs are high; the latter is costly but easy to automate. ...
... In the physical model test, the x-axis just coincides with the main slip direction of the landslide, so it is reduced to 2-D displacement measurement, which is also consistent with most physical model test environments. However, this is not to say that the flexible inclinometer probe is only suitable for measurements with a single direction [27,31]. According to the principle of conversion, the combined displacement can be converted from both x-angle and y-angle by Equation (6). ...
Article
Full-text available
The physical model test of landslides is important for studying landslide structural damage, and parameter measurement is key in this process. To meet the measurement requirements for deep displacement in landslide physical models, an automatic flexible inclinometer probe with good coupling and large deformation capacity was designed. The flexible inclinometer probe consists of several gravity acceleration sensing units that are protected and positioned by silicon encapsulation, all the units are connected to a 485-comunication bus. By sensing the two-axis tilt angle, the direction and magnitude of the displacement for a measurement unit can be calculated, then the overall displacement is accumulated according to all units, integrated from bottom to top in turn. In the conversion from angle to displacement, two spline interpolation methods are introduced to correct and resample the data; one is to interpolate the displacement after conversion, and the other is to interpolate the angle before conversion; compared with the result read from checkered paper, the latter is proved to have a better effect, with an additional condition that the displacement curve move up half the length of the unit. The flexible inclinometer is verified with respect to its principle and arrangement by a laboratory physical model test, and the test results are highly consistent with the actual deformation of the landslide model.
... Sensors more frequently used for landslides monitoring are inertial sensors (accelerometers), soil humidity sensors, and temperature sensors. Some examples of previous works that used accelerometers can be found in [7], [8], [9], [10] and [11]). ...
... The MUMS instrumentation [1] consists of a 'chain' of nodes which are located at known distances from each other and which are connected by an aramid fibre rope. Each node is equipped with both a 3D micro electro-mechanical acceleration sensor (MEMS) and a 3D digital magnetic sensor. ...
Article
The paper illustrates the theoretical basis of a new device called MUMS - Modular Underground Monitoring System - and one of its applications. MUMS has been designed for monitoring of underground displacements through a continuous and automated data acquisition system. MUMS instrumentation can be used to monitor the deformation of natural and artificial slopes as well as geotechnical structures. The device consists of a series of nodes located at known distances along a connecting rope and is installed within a vertical borehole. Each node measures its local rotation relative to the vertical axis by means of a 3D micro electro-mechanical acceleration sensor (MEMS). The direction cosines of each node are calculated in order to determine the 3D shape and deformation of the entire borehole. The paper illustrates an interesting application of MUMS in natural slopes and points out the benefits of the system.
... MUMS (Segalini and Carini 2013) is an automatic inclinometer composed by several nodes at defined distances, linked by a Kevlar rope and a quadrupole electrical cable, that collects multi-parametric data. A 3D MEMS sensor equips tilt nodes, while high precision tilt nodes have an additional 2D electrolytic cell. ...
Conference Paper
This paper presents the preliminary results of a study carried out on an active landslide, which insists on the A16 (E842) Highway, between Campania and Puglia region (South of Italy). The area lies at the foot of a large gravitational mass, classified as “ancient landslide deposit” where a system of landslides, with different types and activity states, are present. It is characterized by the widespread presence of clayey sequences that affect the stability of the slopes looming over the highway. The site has been instrumented with a series of automated sensors, both innovative and traditional, which monitor different physical entities. Furthermore, a photogrammetry survey was carried out with a drone in order to know precisely the geometry of the slope. Once the geotechnical and hydraulic parameters were collected, a 2D finite difference numerical model (FLAC® software) of the slope was set up and a series of back analysis were carried out comparing the model results with those obtained from the monitoring database. Through these back analyses, the choice of the geotechnical parameter was refined and validated. Different physical variables and results are shown into a unique representation, in comparison with the developed model and the geological and geotechnical information. Following the trends of data, the weekly/monthly average displacements and the possible causes (heavy rainfall, raising of the water table), it is possible to study the mechanical behavior of the landslide and establish preliminary warning thresholds, which have to be verified in future. The large number of acquisitions, provided by the automated monitoring system, permits to use a statistical approach in order to identify a good reliability and increase the confidence on the results. The obtained knowledge allows for the automation of the data processing procedure and for the control of the highway stability in near real time.
... For example, the Global Positioning System (GPS) has been increasingly employed in the study of landslide surface movements (Gili et al. 2000;Wang 2011;Huang et al. 2017), but its accuracy is affected by some inherent errors such as clock bias, ionosphere error, and troposphere error (Parkinson 1996). Underground inclinometers are used to determine internal slope changes (Chang et al. 2005;Segalini and Carini 2013) but the used inclinometers to calculate the surface displacement may also cause some uncertainties. These devices are thus limitedly effective for slope failure survey through direct monitoring. ...
Article
Full-text available
Multi-sensor observation is very important for monitoring landslide disasters. Since various surveying techniques are currently available for detecting variational slope activities from different perspectives, studies have focused on integration of multi-source information for the analysing landslide displacements. In this study, a general multi-source data fusion scheme for landslide monitoring based on three-dimensional variation (3DVar) data assimilation was developed. The scheme was used to fuse different observations of Xishancun Landslide in Li County, Sichuan Province, China. First, the displacement observations obtained by a Global Positioning System (GPS) and Borehole Inclinometers (BIs) were assimilated for accurate evaluation of slope activities. Then, slope Stability Index (SI) was introduced to validate the assimilation results within a time interval. SIAssi values calculated using the integration model developed in the present study were compared with SIFS simulated by a physically based landslide model. The correlation coefficient between them ss 0.75, which is larger than those with SIGPS (0.45) or SIBIs (0.41) values determined by the GPS and BIs respectively. The assimilation results are thus confirmed to be more credible for slope stability simulation.
... (IT). The instrumentation is an array composed of different nodes (named Links) connected by a quadrupole electrical and an aramid fiber cable, forming an arbitrarily long chain [18,19]. The device can be equipped with 3D MEMS (Micro Electro-Mechanical Systems), electrolytic cell, piezometer, thermometer sensors, and electronic board. ...
Article
Full-text available
During recent years, the availability of innovative monitoring instrumentation has been a fundamental component in the development of efficient and reliable early warning systems (EWS). In fact, the potential to achieve high sampling frequencies, together with automatic data transmission and elaboration are key features for a near-real time approach. This paper presents a case study located in Central Italy, where the realization of an important state route required a series of preliminary surveys. The monitoring system installed on site included manual inclinometers, automatic modular underground monitoring system (MUMS) inclinometers, piezometers, and geognostic surveys. In particular, data recorded by innovative instrumentation allowed for the detection of major slope displacements that ultimately led to the landslide collapse. The implementation of advanced tools, featuring remote and automatic procedures for data sampling and elaboration, played a key role in the critical event identification and prediction. In fact, thanks to displacement data recorded by the MUMS inclinometer, it was possible to forecast the slope failure that was later confirmed during the following site inspection. Additionally, a numerical analysis was performed to better understand the mechanical behavior of the slope, back-analyze the monitored event, and to assess the stability conditions of the area of interest.
... In order to achieve the objective of developing an innovative tool able to measure directly the tunnel pre-convergence, the authors applied the MUMS technology (Segalini & Carini, 2011;Segalini et al., 2015) to the monitoring of rock mass deformations ahead of excavation front. This system, originally intended to be applied on slope stability problems (Carri et al., 2015), has laid the basis for the production of new instruments for tunnel monitoring purposes (Carri et al., 2017a). ...
Chapter
During a traditional tunnel excavation, the behaviour of the surrounding rock mass is a meaningful evidence of the appropriate design assumptions. Various studies have highlighted the relationship between tunnel convergence and the pre-convergence, which is recognized as the key parameter to understand and control this behaviour. Up to now, the pre-convergence has been assessed with an indirect approach, deriving its values from other parameters. This paper presents a series of laboratory tests performed on a new instrument designed for the direct monitoring of pre-convergence. The tool (called PreConv Array) is based on 3D MEMS sensors and it is designed to be inserted inside an advancing borehole, providing information about the deformation of rock mass ahead the excavation face. The tests were aimed to evaluate the sensitivity, accuracy and uncertainty of the instrumentation, by imposing various deformations to a PreConv Array prototype and comparing the readings with those obtained by a topographic survey.
... The instrumentation described in this paper is based on MUMS (Modular Underground Monitoring System) technology [21,22], developed after several years of researches in the field of geotechnical monitoring by ASE S.r.l., a private company originally born as a spin-off of the University of Parma. This system follows an innovative approach to geotechnical monitoring activities, providing an integrate solution featuring fully automated processes for data acquisition, storage, elaboration, and representation ( Figure 1). ...
Article
Due to the considerable number of uncertainties and to the anisotropic nature of rock masses, tunnel design assumptions should be always validated during the construction phase. This procedure could be performed by means of a regular monitoring of the rock mass deformation around the tunnel face, with particular attention to convergence and preconvergence phenomena. This paper presents the experimental data obtained through an automatic monitoring system composed of two devices, called PreConv Array and Cir Array, respectively developed for the direct monitoring of pre-convergence ahead of the excavation front, and the convergence of the tunnel profile in a specific section. Each device is connected to an acquisition control unit that queries the sensors and automatically sends the data to an elaboration center at predefined time intervals. The automated elaboration approach provides a complete and immediate description of the rock mass behavior.
... Cir Array is an innovative monitoring tool developed by ASE S.r.l. and based on MUMS technology (Modular Underground Monitoring System) (Segalini and Carini, 2013;Segalini et al., 2014). It is designed for near-real time monitoring of convergence phenomena and localized deformations taking place in a specific tunnel section. ...
Conference Paper
Tunnels and underground structures are one of the most important components of road and railway networks, especially near urban areas. For this reason, it is particularly important to identify potentially hazardous conditions in order to guarantee the structure's durability and practicability. This paper presents a case study where a seismic event severely damaged a road tunnel located in Central Italy, impairing its accessibility and leading to its closure for safety reasons. Following the damage assessment, and given the importance of this specific structure, it was decided to perform a series of renovation works aimed to restore the tunnel's operability. In this context, an innovative automatic monitoring device, able to measure the structure deformation, was installed in a critical section of the road tunnel. This instrument, called Cir Array, is specifically designed for near-real time monitoring of convergence phenomena and localized deformations inside underground structures, obtaining accurate and reliable results during their operational phase. The instrumentation provided useful information about the structure's conditions, playing a major role into assessing the tunnel's accessibility and safety during the renovation works. Moreover, thanks to its automated and high frequency sampling process, it will allow the implementation of dedicated warning procedures related to the passage of the vehicles inside the tunnel.
... Cir Array is an innovative monitoring tool developed by ASE S.r.l. and based on MUMS technology (Modular Underground Monitoring System) (Segalini and Carini, 2013;Segalini et al., 2014). It is designed for near-real time monitoring of convergence phenomena and localized deformations taking place in a specific tunnel section. ...
Article
Full-text available
Tunnels and underground structures are one of the most important components of road and railway networks, especially near urban areas. For this reason, it is particularly important to identify potentially hazardous conditions in order to guarantee the structure's durability and practicability. This paper presents a case study where a seismic event severely damaged a road tunnel located in Central Italy, impairing its accessibility and leading to its closure for safety reasons. Following the damage assessment, and given the importance of this specific structure, it was decided to perform a series of renovation works aimed to restore the tunnel's operability. In this context, an innovative automatic monitoring device, able to measure the structure deformation, was installed in a critical section of the road tunnel. This instrument, called Cir Array, is specifically designed for near-real time monitoring of convergence phenomena and localized deformations inside underground structures, obtaining accurate and reliable results during their operational phase. The instrumentation provided useful information about the structure's conditions, playing a major role into assessing the tunnel's accessibility and safety during the renovation works. Moreover, thanks to its automated and high frequency sampling process, it will allow the implementation of dedicated warning procedures related to the passage of the vehicles inside the tunnel.
... MUMS is an innovative monitoring system developed and patented by ASE S.r.l. (IT), composed of a series of epoxy resin nodes, named Links, connected by an aramid fibre cable and a single quadrupole electrical cable to form an arbitrarily long array of sensors (Segalini and Carini 2013;Segalini et al. 2014). MUMS tools are customizable with respect to sensors number, distance and typology, with the possibility to integrate 3D MEMS (Micro Electro-Mechanical Systems), electrolytic tilt cells, piezometers, barometers and high-resolution thermometers. ...
Conference Paper
Full-text available
Retaining walls are geotechnical structures that frequently interacts with roads, railway lines and motorways, playing a key role in the safety of transport networks in mountain areas. For this reason, monitoring activities aimed to assess the stability condition of these works are extremely important to guarantee the practicability of communication lines, especially during adverse meteorological conditions. In particular, the integration of automatic devices and advanced deep learning algorithms permits to implement early warning measures characterized by high accuracy and the reduction of uncertainties due to a statistical approach to the measure, which significantly improve the system performances. Finally, the remote control of physical entities through a web based platform permits to apply an all new Internet of Natural Hazards (IoNH) approach, which is to be intended as the implementation of IoT (Internet of Things) in the geo-related Hazard field. This paper presents a case study where a reinforced soil retaining wall was instrumented with innovative monitoring tools based on Modular Underground Monitoring System (MUMS) technology in order to control the displacements of the geotechnical structure together with the pore pressure and the temperature, applying Early Warning Procedures at the overcoming of predefined thresholds. In particular, two 15-meter long automatic inclinometers were installed on-site 3 meters apart, each of them composed of 15 multi-parametric tilt sensors spaced 1 meter along the vertical direction and one piezometer at a predefined depth. Among the several features presented by the innovative system selected for this case study, one of the most relevant was the synergic integration of two tilt sensors featuring different resolution and sensitivity, thus obtaining a redundant system, which has been fundamental in the correct evaluation of the results. Should this IoNH approach become diffusely applied, the costs of its implementation would reduce significantly and its valuable support would be beneficial for the whole geotechnical field
... In order to achieve the objective of developing an innovative tool able to measure directly the tunnel pre-convergence, the authors applied the MUMS technology (Segalini & Carini, 2011;Segalini et al., 2015) to the monitoring of rock mass deformations ahead of excavation front. This system, originally intended to be applied on slope stability problems (Carri et al., 2015), has laid the basis for the production of new instruments for tunnel monitoring purposes (Carri et al., 2017a). ...
... It has been developed in order to provide a fully automated system able to manage all operations related to data acquisition, transmission, storage, elaboration and visualization ( Fig. 1). In particular, the proposed methodology is intended to manage devices based on MUMS (Modular Underground Monitoring System) technology [7,8], while its functioning principles could be expanded to other monitoring tools. MUMS instrumentation relies on a series of sensors, embedded in specifically molded epoxy resin nodes (called Links) and connected in order to form an arbitrary long array. ...
Conference Paper
The integration of Internet-of-Things principles, giving the possibility to connect different physical sensors through a communication network, is becoming increasingly important in several fields of application. Within the geotechni-cal framework, one of most productive application of the IoT approach is related to monitoring systems, which can significantly benefit from the possibility to exploit more proficient and reliable connections between sensors, control units and visualization devices. In particular, these advantages allow for the development of advanced Early Warning Systems (EWS) able to communicate with high efficiency the occurrence of a potentially critical event, getting even closer to a real-time approach. An innovative application of IoT technologies to geotech-nical monitoring is presented, involving the integration of modern devices with data loggers that can be controlled from remote, dedicated software implementing machine-learning algorithms, and web-based visualization platforms. The result of these components integration is a fully automated and network-connected system , defined Internet of Natural Hazards (IoNH). One application deals with the installation of a mechanical trigger on a rockfall barrier, in order to detect an impact on the structure and consequently read all installed sensors, alerting those responsible of the monitoring activity. Another case study includes the monitoring of a building with tilt-based sensors, automatically identifying the overcoming of predefined alert thresholds. The software is able to disseminate automatically a message in case of an overcoming of these levels and to activate different alarm devices (e.g. sirens, traffic lights, etc.).
... In order to achieve the objective of developing an innovative tool able to measure directly the tunnel pre-convergence, the authors applied the MUMS technology (Segalini & Carini, 2011;Segalini et al., 2015) to the monitoring of rock mass deformations ahead of excavation front. This system, originally intended to be applied on slope stability problems (Carri et al., 2015), has laid the basis for the production of new instruments for tunnel monitoring purposes (Carri et al., 2017a). ...
... The functioning principle of the presented monitoring instrumentation derives from MUMS (Modular Underground Monitoring System) technology, developed by ASE S.r.l., a private company originally born as a spin-off of the University of Parma. This system was created for the development of an automated inclinometer, designed to replace manual measurement procedures, and has been used as a basis for the development of several other geotechnical monitoring devices, including buildings, geotechnical structures, and underground constructions [12,13] ...
Article
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Tunnels are complex constructions, generally built in difficult geological contexts. When dealing with underground structures, the study of ground deformations is a key aspect to consider in order to guarantee safety during the tunnel excavation and construction quality. One of the main aspects to investigate is related to the development of preconvergence phenomena in the advance core, i.e. deformations involving the volume of rock mass ahead of the tunnel face. This paper presents the application of a new monitoring tool specifically developed to measure preconvergence effects during the excavation phases with a direct approach. The device, called PreConv Array, consists of a series of 3D MEMS (Micro Electro-Mechanical System) and temperature sensors. The system takes advantage of automated procedures for data acquisition, elaboration, and representation, thus achieving a near-real time monitoring of the ground differential vertical settlements ahead of the excavated face. Monitoring results reported in this paper are related to the installation of a PreConv Array during the excavation phases of a road tunnel located in Northern Italy. The collected data allowed to highlight the displacements of the tunnel crown in correspondence of each step of the excavation works. Moreover, the comparison with theoretical Longitudinal Deformation Profiles (LDP) evidenced the good correspondence between PreConv data and the theoretical curves.
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The in situ monitoring of displacement variation is important for studying the seabed subsidence mechanism. To meet the multi-point measurement requirements for vertical displacement in subsidence monitoring of the seabed surface, a Micro-Electro-Mechanical Systems accelerometer array was designed. By sensing the tilt angles, displacements on the array can be calculated. The subsidence is calculated as the difference in the displacements from the initial values. To improve the accuracy of the displacement calculation, a calibration model of the tilt angle was presented. The model parameters are computed through a least squares estimation method, which is solved by the Levenberg-Marquardt algorithm. Experimental results show that the calibration model performs excellently with the maximum error of tilt angle being less than 1° in the measurement range (−90°, 90°). The displacement measurement accuracy of the array (2.1 m long) is almost less than 1 cm. Thus, the results show a strong agreement between the detected data and actual deformation in the test.
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Landslide displacement monitoring plays a fundamental role in the study of landslide evolution mechanisms, forecasting, risk assessment, prevention, and control. To fill the deficiencies of traditional instrumentation for measuring landslide displacement distributed along lateral direction, a landslide displacement measurement method based on deformation-coupled pipeline trajectory measurement is proposed, and a pipeline trajectory inertial measurement instrument is developed. The developed instrument, primarily comprised of a single shaft gyro, two axis accelerometers, and an external roller encoder, is designed as an axial half strapdown-radial half platform structure combined with a mechanical gravity platform. This structure avoids the singularity of pitch angle and roll angle and can expediently calculate a pipeline trajectory with an Eulerian transformation when obtaining several basic physical variables, e.g., the axial linear velocity, pitch angle, roll angle, and azimuth angle. Additionally, the pipeline trajectory, measured at different times, possesses the ability to reflect the displacement evolution feature of landslides. The results of prototype simulation tests imply a single measurement accuracy of a 12 cm/100 m span and a singly periodic multiple (more than five times) measurement accuracy of a 3 cm/100 m span, which meets medium-precision displacement measurement requirements for a landslide. Additionally, the finished instrument has been successfully applied to the deformation monitoring of the Majiagou I# landslide, which further verifies its feasibility and offers a reference for similar landslides.
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This paper introduces an innovative and economically convenient measurement system that is based on a novelty method of installation, operation and remote control technology for ground watertable measurement. The technology is based on TDR (Time Domain Reflectometry) that employ a unique hollow coaxial cable. Installation is performed by CPT/DP penetration testing equipment, which in its nature, is relatively light, versatile, operative, and is not demanding of manpower or machinery. This method brings benefit to currently unreachable sites ex. steep slopes, places with little or no road access, option for setting up additional probes on existing structures etc., as the method doesn't require conventionally truck-mounted drilling rigs. Electronic origin of measurement offer the possibility of probe networking, remote sensing, automatic data acquisition and evaluation through developed software. Proposed measurement system has been laboratory tested, calibrated and installed on various sites over past 6 years in Slovak republic.
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Gallerie e opere sotterranee sono tra gli elementi più rilevanti nelle reti stradali e ferroviarie, in particolare nei pressi di aree urbane. Per questo motivo, è particolarmente importante identificare potenziali condizioni di pericolosità per garantire la stabilità della struttura e permetterne l'utilizzo in sicurezza. In questo articolo è presentato il caso di studio di una galleria danneggiata dal terremoto che ha interessato il Centro Italia nel 2016. Tra i vari interventi di indagine e ripristino che hanno fatto seguito a tale evento è stata prevista l'installazione di uno strumento di monitoraggio, chiamato Cir Array, progettato appositamente per il monitoraggio automatico in near-real time dei fenomeni di convergenza e deformazioni in opere sotterranee. I dati raccolti hanno fornito utili informazioni riguardo le condizioni della struttura durante i lavori di ripristino. Inoltre, la possibilità di eseguire misure in automatico e ad alta frequenza permetterà la futura implementazione di soglie di allarme e sistemi di allertamento.
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Slope inclinometers/indicators are used to determine the magnitude, rate, direction, depth, and type of landslide movement. This information is usually vitally important for understanding the cause, behavior, and remediation of a landslide. However, many inclinometer measurements fail to achieve these intended aims because of lack of appreciation of the many factors that need to be correctly implemented during installation, monitoring, and data reduction to yield useful data. This paper presents some guidelines for understanding, installing, and interpreting slope inclinometers and presents three case histories that illustrate some of the pitfalls that can develop if these guidelines are not followed.
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Following the flood events occurred in the 1993 autumn, a landslide affecting the village of Montaldo di Cosola was reactivated. Montaldo di Cosola is a small village located in North-Western Italy, on the Appennines Mountains. Historical data report of at least another similar episode occurred about one century ago.The landslide takes place over debris deposits, which are about 20–35 m deep, produced by an ancient landslide event. Underneath these debris deposits there is an altered layer of the calcareous-marly substratum of the Antola formation. The landslide, almost certainly triggered by the incision of the torrent Rio Montaldo, has a probable rotational geometry and takes place through slow and progressive continuous movements. The landslide typology impedes a precise dimensional definition. Only the order of magnitude of the main scarp width, which is of hundreds of meters, and the order of magnitude of the landslide volume, which is of some hundreds of thousands of cubic meters, can be indicated.A complex monitoring network has been installed in the area. This network includes an automatic inclinometric system (AIS) that automatically performs measurements, twice a day, along the entire length of a pipe that is 45 m deep. Measurements are taken every 50 cm and are then broadcasted to a remote station located in Torino.After the exceptional meteorological events occurred in October 2000, the AIS measured significant movements that have not yet stopped. On the basis of these available data it has been possible to locate the sliding surface at a depth of about 13 m at the level of a sandy–silty layer with some clay lenses inside. The movements measurements performed so far reveal a good correlation with the rainfalls. In particular it has been possible to identify a time lag of about 8–9 days between the occurrence of a rainfall peak and the corresponding peak in the recorded movements that were produced by these rainfalls.
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