Measuring VOC Transport using SIMCV

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Geo-Environmental Research
Calibrated Soil Test Bed
Measuring VOC Transport using SIM-CV
Purpose The mesoscale soil test bed located in
the Harry Morrison Civil Engineering Laboratory
(HML) was designed for controlled testing and
validation of new and existing soils
instrumentation.
Purpose To provide a method for collecting data
at rates suitable for calibrating newly developed
sensors used to detect and monitor containments.
Construction of the test bed began with the
removal of a section of the flooring, allowing an
8-ft diameter, 7-ft deep pre-cast concrete vault
to be placed. After installation, the bottom 10
cm of the vault was filled with a gravel drainage
layer imbedded with a system of slotted pipes for
drainage. This system allows water to be pumped
in and out of the soil deposit through a
standpipe to achieve various soil moisture
regimes. To create a homogeneous testing
environment, a sandy soil was uniformly deposited
in 10-cm lifts on top of the drainage layer to a
total deposit depth of 150 cm. Each layer was
uniformly compacted to densify the deposit. The
test bed is instrumented with 18 time domain
reflectometry (TDR) probes for continuous
measurement of moisture content and 14
tensiometers for measurement of water pressures
under unsaturated conditions. A wetting
experiment has been completed and the deposit is
currently drying by means of surface evaporation
and a ventilation system.

• Advantages of the System
• An improved measurement method that combines
  the high sampling rate of HRIMS with the high
  resolution and selectivity of mass spectrometry
  analysis
• Soil column experiments for simulated field
  conditions
• Simultaneous measurements using a GC/MS for
  sensor validation
• Investigation of multiple compound interactions
  during chemical reactions