Hillis-Carnes Offers In-House Microgravity Testing

Hillis-Carnes is excited to announce that our firm recently purchased a Scintrex CG-6 Microgravity unit to perform in-house microgravity (MG) testing. This type of geophysical equipment can perform numerous applications during subsurface investigations, especially those done within buildings where space and access are limited.  The MG equipment is non-destructive and does not require large open areas to perform testing. Another advantage for occupied sites is this geophysical method can function when placed on concrete and inside buildings, because unlike Electrical Resistivity (ER) geophysical equipment, microgravity does not require cables and steel pins to be placed in the ground. MG equipment is also typically utilized to perform hydrogeologic evaluations, where soils may migrate due to the movement of water.

Microgravity Testing records minute differences in gravitational pull at various locations and is useful in delineating karst activity, such as sinkholes, caves, etc. Identifying karst activity is critical when performing geotechnical engineering services and subsurface exploration of a proposed development. The results generated from this unit can be displayed in colorized contour maps based upon the microgal levels.  Microgravity results are displayed in a way that blue areas represent potentially soft/loose/saturated soils, while bright oranges and red colors represent areas of relatively hard, dense, slightly weathered to fresh rock. The CG-6 also uses a fused quartz spring system. The gravitational force on the proof-mass is balanced by a spring and an electrostatic restoring force.  The inherent strength and excellent elastic properties of fused quartz, coupled with the limit stops around the proof-mass, permit the instrument to be operated without clamping. The equipment is also outfitted with a durable shock mount system to provide added protection, prevent interference from external factors and ensure more accurate results. The gravity data is corrected for latitude, elevation, topography and tides to detect anomalies caused by the subsurface density contrasts.

These enhanced geophysical equipment resources significantly enhance our Geotechnical Services capability.  Since project sites have unique physical limitations, the ability to provide a variety of tests, including ER testing, seismic refraction/reflection surveys, and MG testing, allows us to meet the needs of clients and adapt to varied site characteristics. With the Scintrex CG-6 Microgravity unit in our geophysical arsenal and ability to perform in-house microgravity testing, we can now provide accurate results and solutions whenever we are dealing with sites that are inside of structures or with limited access. Contact us today for more information!