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Engineering & Environmental Information Services.
Geophysical consultants and contractors, Instrumentation and monitoring, Vibration & noise. |
Seismics
Ferroscan
Microgravity
Thermal resistivity
Other geophysical survey services:-
We also have expertise in the following techniques and can recommend them if the site suits:-
Seismic refraction / reflection:-
By imparting a large energy pulse into the ground using a hammer, drop weight or cartridge explosive a series of geophones are used to detect the seismic energy returning to the ground surface. The energy arrives at the geophones either directly along the ground surface, by reflection from layers or interfaces or by refraction from the top of a layer. Using the return time of the energy we can calculate velocity, model the presence of layers, and find ground stiffness and rippability. Using continuous surface waves (CSWS) generated by a vibrating mass it is possible to obtain ground stiffness profiles for geotechnical purposes within 50 minutes. The method can be used on contaminated land and difficult sites as it is non-intrusive.
Ferroscan :-
| Although not usually classed as geophysics, this tool made by Hilti uses electromagnetic principals to locate steel reinforcement in concrete. The instrument gives an almost instant visual image - very useful for on-site decision making and concrete slab and column surveys |
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Microgravity:-
Measurements of local gravitational field can be taken with exceptionally sensitive instruments. By measuring the variation in gravity over a tight grid its possible to model the data to obtain information on the location of voids, infilled karst features, buried channels and buried structures. Although a relatively slow method due to the precise levelling needed between each survey station the output can be worthwhile since the system measures passively and is not affected by electrical or conductive interference and can be used in industrial buildings where vibration is kept to a minimum.
Thermal resistivity and buried cables:-
Cable engineers need to understand the relationships between the soil and its ability to disperse heat generated by buried high voltage cables. A number of incidents have occurred in the past where a the soil around a cable under high load was not able to conduct heat quickly enough to prevent thermal runaway and subsequent damage. We use the KD2 thermal resistivity probe to provide in-situ measurements of the surrounding materials prior to cable installation. This approach allows the correct cable rating calculations to be performed to prove the viability of the native infill or whether specialist trench infill material is required.