Context
The destabilisation of a 150-metre-high cutting, formed as part of the construction of the A-63 motorway in Asturias, Northern Spain, has required the design and construction of a retaining structure to ensure the safe consolidation of the unstable ground.
The works, which are overseen by the Spanish Ministry of Transport and Sustainable Mobility and carried out by the company DRAGADOS, include the installation of a reinforced concrete wall anchored to the ground. Various containment and support systems adapted to the characteristics of the terrain will also be installed, such as triple torsion meshes, cable nets, soil nails and shotcrete.
To guarantee both the effectiveness of these measures and the safety of the work, it is essential that the slope movements, interstitial pressures caused by the groundwater, as well as the stability of the retaining wall and its anchorages are monitored in a continuous automated way.
Solution
Empírica Ingenieros S.L., a civil engineering company specialised in geotechnics and instrumentation, has been chosen to carry out this project using instrumentation consisting of:
- inclinometers* connected in series to monitor ground movements
- closed piezometers* to measure interstitial pressures
- clinometers to control possible inclinations of the wall and load cells to evaluate the tension in the selected anchorages
*The inclinometers and piezometers reach depths of greater than 50 metres.
In total, 372 Worldsensing sensors will be installed: these will be automated via a connection to wireless dataloggers, each one adapted to the type of instrument (digital, vibrating wire or piconode dataloggers). These dataloggers are linked to a gateway that is responsible for collecting and transmitting the data.
The information collected can be accessed via the gateway application, a private data visualisation platform and, specifically, via the Celosia platform, which allows monitoring of the specific structures and geotechnical elements of the Spanish Ministry of Transport and Sustainable Mobility.
“The Worldsensing monitoring system allows parameters to be checked with high reliability, and measurements to be compared to the design values and control limits. With over 300 channels it can provide results every 3 hours, requiring only occasional maintenance and error correction.”
State Road Demarcation Technicians in Asturias, Spain.
Benefits
Obtaining data in remote and difficult to access locations is always a challenge. The automated monitoring system allows technicians to access up-to-date data in real-time, significantly increasing the frequency of measurements and allowing problems to be detected more quickly and corrective action to be taken more effectively.
Automatic measurement and transmission simplify and reduce long-term costs by facilitating continuous monitoring of the cuttings even during the service life of the motorway after the works have been completed. As a result, the community benefits from a key development infrastructure project in which safety is guaranteed via constant monitoring of the cuttings and their behaviour.
Advantages
- The automated monitoring system provides technicians with up-to-date information in real time, facilitating early detection of problems and allowing corrective actions to be taken more quickly.
- Automatic measurement and transmission ensure constant monitoring of the cuttings, even after completion of the works, thus maintaining the safety of the infrastructure throughout its service life.
- Automation of the measurement and transmission processes significantly reduces long-term operational and maintenance costs.
- The constant monitoring of the behaviour of the cuttings ensures the stability of the work and provides greater safety for the community, minimising any potential risks related to unstable ground.