In the course its development Groupe Géotec has also come to specialize in geophysics through the acquisition of the company ME2i in 2009.
Created in 1985 by a group of engineers with experience in measurement, instrumentation, monitoring and geophysics, the subsidiary is particularly active in fields related to soil, subsoil and engineering works.
ME2i provides services throughout France and abroad for geophysical tests and measurements, diagnostics of building or civil engineering works and issues relating to the environment and natural resources.
ME2i specializes in geophysical measurements, geodynamic and geostatic measurements in boreholes and structural diagnostics. The subsidiary also provides instrumentation services.
Applied geophysics is the science that studies the structure of the ground by measuring physical parameters using non-destructive surface methods.
ME2i performs most currently available geophysical techniques to address the following issues:
- Stratigraphy and geology for linear or surface plots: seismic refraction, electrical tomography, electrical sounding, electromagnetic methods, and low and medium frequency georadar.
- Searching for cavities and man-made voids: microgravimetry, electrical tomography, low and medium frequency georadar.
- Earthmoving capacity of soil (rippability) and slope stability: seismic refraction, EM31, EM34 and EM38 electromagnetic methods.
- Research in water, pollution…: electrical tomography, spontaneous polarization
- Pyrotechnic security: low and medium frequency georadar, electromagnetic and magnetic methods.
- Locating conductive bodies: electrical tomography, electrical sounding, spontaneous polarization, electromagnetic methods EM31, EM34 and EM38.
- Determination of dynamic soil parameters: cross-hole tests, down-hole tests, seismic refraction and MASW
ME2i provides instrumentation for sensitive structures in order to monitor them over time.
The teams instrument boreholes, tunnels, engineering works and any other sensitive structures.
- Vibrations: vibration impact studies, real-time vibration monitoring, vibration excitation of structures.
- Monitoring of cracks over time using fissurometry or extensometry.
- Landslide monitoring using inclinometry.
Geodynamic and geostatic measurements in boreholes
ME2i performs various drilling and dynamic or static soil parameter measurements in collaboration with a drilling company.
Dilatometry is an in situ rock mechanics test (in a borehole) that indirectly measures the elastic modulus of the rock. ME2i provides this service in compliance with the AFNOR XP P 94-443-1 and 2 standard of February 2002 and the NF EN ISO 22476-5 standard of March 2013.
A well log is a record of a physical or geological feature determined by depth. It is therefore carried out in a geotechnical borehole. ME2i uses gamma-ray logging to measure the natural radioactivity of the ground.
Cross-hole, down-hole and up-hole are geophysical drilling methods that allow the dynamic moduli of soils to be obtained via compressional and shear wave velocities. ME2i performs this measurement in accordance with ASTM standards.
The parallel seismic method (PSM) makes it possible to estimate the depth and quality of the material of a foundation, even with a structure on top. ME2i carries out this measurement in accordance with the AFNOR NF P 94-160-3 standard.
As civil engineering structures are not always well documented, ME2i offers methods to remove a number of unknowns.
For example, the teams carry out measurements in order to:
- Determine the layout and type of reinforcement of a concrete slab using the high frequency radar method.
- Evaluate the fracturing in a block of concrete using the ultrasound method.
- Estimate the depth of a deep foundation by MSP, impedance or even by reflection (AFNOR NF P 94-160-2 3 & 4 standards).
- Locate buried networks by low and medium frequency ground-penetrating radar and by radiodetection.
- Refraction and MASW equipment consisting of a Geometrics Geode, 12 or 24 inter-trace resistivity cables of 2mv, 5m or 10m and 10Hz geophones for refraction and 4.5Hz geophones for MASW.
- 1m 12 -rack PSM inter-trace resistivity cables.
- Electrical methods equipment consisting of a Terrameter LS, 16 or 32 channel electric resistivity cables with 2m or 5m inter-electrode spacing and stainless steel electrodes.
- Rental of all types of electromagnetic measuring equipment.
- Gravimeter equipment consisting of a Scintrex CG5 gravimeter and a Leica Rugby 820 laser surveying set.
- Georadar equipment consisting of SIR 3000, SIR 4000 and UtilityScanDF acquisition systems and GSSI 400MHz, 200MHz and dual frequency 300-800MHz georadar antennas on a trolley with an encoder wheel.
- StructureScan 1.6GHz radar antenna for reinforced concrete detection.
- Radiosensing equipment composed of a TX10 generator and an RD800PDL receiver from Radiodétection/SPX as well as a Radiodétection/SPX Flexitrace needle.
- Dilatometry equipment consisting of dilatometers that can be fitted with 90mm or 95mm diameter membranes and Dilaroc data logger from RockTest.
- Gamma-ray equipment composed of Gamma-ray probes, transmitter and an data logger.
- Cross-hole/down-hole equipment composed of a CH emitter probe with air packer, an SBS42 sparker emitter probe, an IPG5000 sparker generator, and receiver probes with air packer or lamella.
- Complete set of inclinometry equipment from Glötzl consisting of a reading station, 2 inclinometer probes and a 100m cable.
- Vibration equipment consisting of an Instrunet 16-channel data logger, 4.5Hz triaxial geophones and 1Hz geophones.
- Ultrasonic equipment consisting of a Pundit transceiver box, 24kHz, 54kHz or 1MHz transducers and a PicoScope 5000 or Instrunet digital oscilloscope.
- A force hammer.
- All types of crack monitoring gauges.
- Extensometers of various sizes.
For data processing, the engineering teams use commercial software developed by firms specializing in geophysics and software developed in-house:
- The SeisImager suite composed of Pickwin for arrival pointing and Plotrefa for model calculation and result generation as well as WaveEq for the MASW. GeoSoft's WinSism may also be used for seismic refraction.
- Res2DInv by H. Loke for reversing electrical panels. IP2Win for processing electrical sounding.
- Geonics software: DAT31W for the EM31, DAT34W for the EM34, DAT38W for the EM38 and DAT61MK2 for the EM61.
- Radan 7 from GSSI.
- PicoScope software.
- Surfer 12 from Golden Software for interpolations and the presentation of results.
- AutoCad Lite 2015 for blueprint editing.
- Software developed in-house.
ME2I has 5 employees, including 4 geophysical engineers.
In order to be able to work on the various regulated sites, they have the following authorisations:
- Electrical risk H0-B0.
- Risk prevention in EDF power plants outside level 1 controlled areas (M1 training).
- Working on sites with chemical risks (N1 training).
- Certificate of competence for working near networks (AIPR designer).
- Initial Common Nuclear Knowledge Level 1 (SCN1) and Complementary Quality Safety (CSQ) training: HN1.
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