Measures soil conductivity and probing speed simultaneously.
Greatly reduces soil core required to characterize lithology.
Real-time, on-screen log during probing.
Cost-effective alternative to borehole logging or cone penetrometers.
Expendable dipole allows retraction grouting to seal logging holes.
Designed for percussion probing.
Spreadsheet compatible data storage.
FC 4000 Specs
Vertical Resolution
0.05 ft
0.02 m
Data Rate
20 samples per second
Maximum Depth
80 ft.
24 m
Power Requirements
90-230VAC @ 3A
Operating System
DOS
Computer Hardware
3.5 in. Floppy Drive
Dimensions
17 in. x 7.5 in. x 13.5 in.
432 mm x 191 mm x 343 mm
Weight
18.5 lbs.
8 kg
The EC probes come in two different configurations, Dipole Array and Wenner Array,
with the same theory of operation. A current is sent through the formation between
two probe contacts. This current is measured along with the voltage that results
(Info mouse over). The conductivity is a ratio of current to voltage times a
constant. The resulting reading is in milli-Siemens per meter (mS/m).
The conductivity of soils is different for each type of media. Finer grained
sediments, such as silts or clays, will have a higher EC signal. While coarser
grained sediments, sands and gravel, will have a lower EC signal. The coarser
grained sediments will allow the migration of contaminants and the finer grained
sediments will trap the contaminant. The EC system is a powerful tool when used
properly. The EC gives the investigator real-time, on-screen logs allowing onsite
decisions.
Soil conductivity and resistivity (the inverse of conductivity) have long been
used as tools to classify soils. The power of this tool stems from the fact that
higher electrical conductivities are representative of finer grained sediments,
such as silts or clays, while sands and gravels are characterized by distinctly
lower electrical conductivities. A few site specific core samples, either from
discrete depths or a continuous core, can be used to verify the lithology represented
by electrical conductivity values at a site. The electrical logs are then correlated
across the site to show changes in thickness or elevation of lithologic units
of interest. Soil conductivity logging continues to increase in usage because
conductivity logging can be efficiently performed with the highly mobile and
cost-effective percussion probing equipment. . . the Direct Image® Electrical
Conductivity (EC) System.
EC logs are used to define zones of lower conductivity,
equivalent to coarser grained, more permeable sediments, which will allow
the movement of contaminants (hydrocarbons, chlorinated VOCs, or metals)
in the subsurface. The lithologic information gathered with the Conductivity
System can be used to aid the investigator in understanding the movement
and location of contaminants in the subsurface. This information will also
assist in the proper placement of monitoring or extraction wells.
