Compaction Remediation for Construction Sites
jonathan Chaplin,
Associate Professor
David Fick, Undergraduate Student
Reid Pulley, Graduate Student
Funding Source
Minnesota Department of Transportation
Objectives
The goal of this project is to develop a sub-soiling
regimen that will enhance and be compatible with existing
erosion control
measures. The specific research objectives are:
- To assess
the degree of compaction using a tractor mounted soil
cone penetrometer.
- To establish test plots of approximately one acre
in size, which will be sub-soiled before topsoil is replaced,
before
application of erosion blankets, and after vegetation
is established on different plots. Plots will be located
on sites
that represent
the major groups of sand, silt, and clay. Early screening
will be used to examine the soil profile to determine
the tillage
needed. Test plots will not be uniform in dimension
due to width restraints that may be imposed at the site.
- To measure
soil cone index and infiltration rate for each test plot
and quantify vegetative growth as an index
of tillage
benefit.
Need or Impact
Construction activities cause soil compaction,
which in turn prevents water from infiltrating into the soil
and inhibits
the establishment of plants after the construction is completed.
Currently water retention ponds are needed in road projects
to capture both water from the roadway and overland flow.
If we can reduce overland flow, we can reduce the size of the
ponds.
This activity, if successful, will become a building block
for use in BMPs that will ensure full vegetative growth post
construction
and save on the cost of reapplication of erosion control measures.
Project
Status
Tillage sites have been established at four locations
in Minnesota. Three tillage systems have been applied at each
of the sites.
The tillage consists of chisel plow, non inverting plow, and
subsoiler. The effects of these tillage activities are being
monitored over time. Soil compaction is measured using a cone
penetrometer and a soil auger. Rainwater infiltration is determined
by timing how long it takes for a column of water to soak
into the tilled soil. The data points are located using GPS
and then
mapped using a computer. An example Cone Index map is shown
above.
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