GEOPHYSICAL INVESTIGATIONS
Geophysical investigations is a complementary soil survey method which is providing supplementary data regarding physical, chemical and electrical properties of the ground.
There are used on a large scale by providing, in addition of directly survey investigations, a complete site prospecting. There are used at different scales on the land and marine domain.
The geophysical methods used for ground surveys are:
Seismic methods:
Applications:
| • | determination of depth to bedrock |
| • | determination of sedimentary basins and basement formations |
| • | mapping geologic strata and anomalous conditions |
| • | determination of in-situ elastic module of soil (if compressional P-wave and shear S-wave velocities are measured) |
Applications:
| • | determination of depth and thickness of geologic strata |
| • | mapping structural and anomalous geologic conditions |
| • | identification of smaller targets such as mines, tunnels, and caves |
| • | identification of investigated site lithology |
| • | identification of hydrocarbon deposits |
| • | identification of soil ruptures, faults and salt domes |
Georadar method:
Ground Penetrating Radar – GPR survey represents a modern non-destructive technology used for soil investigation, waste deposits and underground constructions by saving the environment.
The application domains which are using this method are various: engineering geology, hydrogeology and hydrology, constructions and civil engineering, archeology and environmental protection.
Applications:
| • | cables and metallic and nonmetallic goods locates (pipes, etc.), reservoirs and holes |
| • | faults, ruptures in soil and concrete structures and other composite materials locates |
| • | resistance structures and reinforced concrete locates |
| • | road-bed studies |
| • | localizarea corpurilor si obiectivelor ingropate |
| • | detecting and mapping the depth of water table, contaminant plumes, buried wastes, and drums |
| • | detect and limit the polluted areas influenced by hydrocarbons or different chemical solutions from soil and subsoil |
| • | determine the geological structures, lithological changes and tectonically accidents |
| • | determine the caves in rock massifs |
| • | locate the level extended micro tectonically accidents in caves and galleries and their time evolution |
| • | mapping the underground water nappe |
| • | detecte the drains of pipes |
Geoelectrical methods:
The electrical resistivity method is one of the most used geoelectrical methods.
Applications:
| • | determine the depth and thickness of geologic strata |
| • | detect lateral changes and locate anomalous geologic conditions |
| • | identification of soil and underground water contamination |
| • | separating of salt and fresh water |
| • | mapping clayed and sandy deposits |
| • | exploring the deposits mineralization |
| • | mapping the depth of water table |
| • | identification of soil ruptures |
vertical electric sounding (SEV)
geoelectrical methods of self potential and natural (SP/NP)
induced polarization method (IP)