Geophysical Exploration RNDr. Robert Votoček, RNDr. Jiří Nedvěd

1. Geophysical ExplorationRNDr. Robert Votoček, RNDr. Jiří Nedvěd

2. The application of geophysical methods to the problems of engineering, geological and hydrogeological investigation enjoy a long-standing in our practice. The first work of this kind was carried out in 1946. The SG-Geotechnika has had its own equipment and experts for geophysical wall loggin since 1970. • The geophysics allows us to extrapolate the data obtained from boreholes, galleries and tests for more accurate interpretation.

3. Complex of used method depends on solved problematics and includes followings methods: • Geoelectric • Seismic • Georadar • Geomagnetic • Termometric • TV probe in borehole • Special underground methods (tunnels, galleries, caverns)

4. Optimal choose of methods, procedures and range of works, which are necessary for fulfilment of Your requirements, are applied mainly in followings branches: • Geotechnics • Environment • Hydrogeology • Building industry • Investigation of mineral raw material deposits • Archaeology

5. Hydrogeology • resource searching, borehole and new well localisation • water development • We qurantee followings usefull data by geophysical measuring: •    saturated and faulted zones course •    quartenary sediments and weathering cover thickness •    thickness and area of sandy collector in clay sediments •    bedrock depth–supporting horizon course •    ground water depth and direction of move •    efficiency of waterproof measures in the surface and underground objects andpipelinecistern •    technical condition of boreholes (perforation)

6. In situ measuring by plant RS-100 M Resistar – multi electrode cable system

8. Geotechnics, Engineer geology • foundations soils investigation • line buildings investigation (highways, roads, railways,pipelines) • undergound buildings and dams investigation • slope stability investigation • We qurantee followings usefull data by geophysical measuring: • geological characteristic of the territory (rock types, depth and degree of weathered area, faulted zones) •    physical and mechanical properties of foundations soils (massif anizotropy, strength and deformation characteristics, rocks rippability and excavation) •    compaction fillings control •    slope stability (plane and spatial estimation of slope deformations) •    forecast of natural arch formation of caverns and galleries, stability of building hole walls, documentation galleries and feeders • cable and pipeline route location •    presence and size nonregistered voids, caverns, old mines • pyrotechnicinvestigation • TV borehole viewing (cavern direction and slope)

9. Geotechnics, Engineer geology In situ measuring refraction survey (SRR), plant Geode-24, co.Geometrics Ltd.-USA

10. Seismic cross sections – seismic velocity isolines

11. Seismic cross sections – seismic velocity isolines

12. Georadar measuring in boreholes in tomographic mode, SIR-20 (GSSI) plant

13. Example of georadar tomography – data distribution of relative permittivity

14. Environment • discovering of contamination rate and size •    rock environment clearance •    borehole positioning • We qurantee followings usefull data by geophysical and geochemical measuring: •    thickness and character of sand sediments •    depth of weathering area and relief uderlaing rocks •    ground water move direction •    soil contamination area •    water aggressivity, corrodibility, erratic flows presence •    waterproof measure efficiency of surface and underground objects, borehole and pipeline cistern tightness •    technical condition of boreholes (perforation)

16. Seismic tomography on dam – seismic velocity isolines

17. Environment corrosion measuring – magnitude, direction and density of stray earth currents

18. Seismic cross sections – seismic velocity isolines

19. Building industry, investigation of mineral raw material deposits, archaeology •    identification of structure and tectonic properties •    rocks elastic properties determination •    strength and rippability of rocks •    monitoring and determining of environment corrosion degree • pyrotechnic investigation •    layers direction and slope determinaton in boreholes •    land radon index measuring for planning permission and buildings acceptance certificate •    surface and shallow undersurface temperature measuring •    building constructions and line buildings diagnosis

20. Whole results of geophysical measuring above undermining area

21. Georadar measuring interpretation, Charles bridge, pile n. 7

22. Seismic tomoraphy, Charles bridge, pile n.7 – seismic velocity isolines

23. Interpretation of georadar measuring, Vltava river bed contour lines and point anomaly

24. Georadar measuring on railway, pulseEKKO 1000 (Sensors&software)

25. Example of georadar measuring on railway interpretation

26. Measuring by georadar SIR-20 (GSSI USA) on road

27. Example of the interpretation and data handling of radar data in form of the deep cut, roadway I/37.

28. Deformation of road subgrade layer on road I/26 detected by georadar measuring

29. 3-dimensional view of georadar data, Kutná Hora, archaeology investigation

30. Pile integrity test – SIT method

31. Dipole electromagnetic profiling DEMP, plant DIKO (EM – 31), Geofyzika Brno