Permanent Geoelectric Monitoring Systems

G.Re.T.A.. - Geo REsistivimeter for Time-lapse Analysis - is the only tool for permanent geoelectric monitoring of the conditions of large tracts of subsoil on the market. It was developed and tested by LSI LASTEM in collaboration with the Politecnico di Milano. The fixed and permanent installation (as well as autonomous from the energy point of view) of the G.Re.T.A. it allows to keep under control and to follow in time the evolution of the conductivity profile of a large portion of land functional to its characterization in terms of water content, presence of cavities, state of fracturing of rock masses, texture and lithology of clusters rocky and more generally the presence of anomalies. The system is able to automatically send alarm messages when pre-established thresholds are exceeded and can also be configured remotely. The execution of a series of resistivity profiles, combined and continuous with the same interelectrodic spacing, allows the realization of 3D resistivity maps.

Fields of Application: EARTHEN DAM FAILURES RISK

G.Re.T.A. allows the continuous monitoring of the earthen dams, leeves and embankment conditions, allowing to identify any anomalies and give an immediate warning in case of dangerous water infiltrations, the main responsible for breaks and landslides.

Fields of Application: CONTAMINATION RISK

The G.Re.T.A. system allows the continuous monitoring of the characteristics of the terrain, allowing to identify any anomalies due to infiltration of pollutants and give an immediate alert.

Fields of Application: LANDSLIDES RISK 

It is possible to directly monitor soil behavior in real time analyzing the resistivity and the water content of the soil.

Other fileds of possible application

  • Precision agriculture
  • Monitoring of salt water intrusion in groundwater
  • Monitoring of overt risk situations, such as chasms, underground cavities

A Consolidated Technology: Multielectrode Electric Tomography (ERT)

The method is based on the insertion of an electric field in the ground through electrodes (input electrodes), and the measurement of the voltage in other electrodes (measurement electrodes). From the measure of the voltage it is possible to obtain, through the second law of Ohm, the resistivity value that is a peculiar characteristic of all materials.

The tomographic inversion of the data obtained generates in "output" a two-dimensional or three-dimensional reconstruction of the soil where it is possible to identify any anomalies due to cavities, water bodies, etc., and recognize their shapes, dimensions and spatial distribution

Main Components of G.Re.T.A. Georesistivimeter

Power supply system composed of a solar panel on a pole, batteries and regulator housed in an IP66 box;
Measurement and communication system consisting of dataloggers and modems housed in an IP66 box and two backbones of cables with plate or picket electrodes;
Web based software on LSI LASTEM cloud platform for data visualization and processing, threshold configuration and alert sending system.

Main Technical Features

  • Max 48 electrodes
  • Distance between the electrodes: 1-3 m
  • Measured profile length: 47- 142 m
  • Max measured profile depth: up to 22 m
  • For horizontal installation: one wing plate or picket
  • For vertical installation: three wings plate
  • Measurement configuration: Wenner
  • Solar panel power supply
  • Modem / Router for automatic data transmission
  • Remote control and programming via LSI LASTEM Cloud
  • Alarm management based on pre-defined thresholds

Three types of installation

Horizontal - one wing plate electrodes (a 20/50 cm excavation is required to house the cable with electrodes). After closing the excavation, only the IP 66 boxes and the solar panel remain visible:
  • Requires a small excavation
  • Better adhesion of the electrodes to the ground
  • The line is protected and does not interfere with external agents (people, animals, etc.)
  • Lower Energy Requirement
Horizontal - picket electrodes (cable laid on the ground). In addition to the IP66 boxes and the solar panel, also the cable  remains visible
  • Ease of Installation
  • Ease of possible repositioning of the line
  • Exposed line may interfere with external agents (people, animals etc.)
Vertical - three wings plate electrodes. After closing the excavation, only the IP 66 boxes and the solar panel remain visible:
  • Requires a deep excavation (144 m)
  • Maximum adhesion of the electrodes to the ground
  • The line is protected and does not interfere with external agents (people, animals, etc.)
  • Lower Energy Requirement

Data management

The data is stored and made available in real time via the web, and can therefore be consulted from any Internet access point. Views and configurations directly via the LSI LASTEM Cloud system with geolocation of the installed systems. It is possible to display and store the soil water content values obtained from the real resistivity data processed by the inversion algorithm. Access to data from Smartphones for viewing data and graphics with the Telegram system

SCHEMA GRETA
GRAFICO

Products of Permanent Geoelectric Monitoring Systems
Georesistivimeter fot Time Lapse Analisys for measuring the alteration over time of the soil’s resistivity profile.

G.Re.T.A.

Code: GRT001

Georesistivimeter fot Time Lapse Analisys for measuring the alteration over time of the soil’s resistivity profile.

See