Environmental Engineering Reference
In-Depth Information
fraction essentially sandy). Flow speed in these little rough structures is indeed not
favorable to fine compound fraction sedimentation.
2.
Sediment from road basins
This category gathers every basin type. Let us note that some structures commonly
called ditches have been included in this category since the sediment type have
characteristics closer to basins than to ditches: it is notably the case of every ditch
staying under water.
Sediment Environmental and Geotechnics Characterization
As part of this work about 100 samplings have been carried out on basins and
ditches in France. Hydrocarbons and metal trace element (MTE) contents have
been analyzed. Data from bibliography
[1]
have been used as well.
Regulation threshold values is not available in France for this kind of sediment
before reuse, the proceeding has been as following: for MTE threshold values are
VCI usage sensible (impact value for sensible aim in French). These values, used
until 2006, correspond to those used for polluted sites and soil in a so-called sensitive
context (garden, park, etc.). For hydrocarbons, the used results have been compared to
inert waste landfill thresholds. To complete this classification, material geotechnical
properties have been studied in detail with the help of geotechnical tests: SETRA's
GTR
[2]
makes it possible to grasp reuse of materials in embankment or sub grades,
from various geotechnical parameters. F category organic soil and industrial
by-products corresponds the best to studied materials. Their using possibilities in
engineering structures depend on their organic matter content (OM%). At this stage
we classify this material type in two categories. For organic matter contents above
10%, F12 materials have not characteristics satisfying to be reused in engineering.
For organic matter contents from 3% to 10%, F11 materials may be used under
conditions similar to mineral matter. To characterize slope geotechnical properties
of materials such as road drainage sediment, the following tests have been carried
out on three samples:
Grain size analysis
Eighty micrometer fraction analysis
Methylene blue value
Initial moisture
Proctor test
Moisture Analysis
The open air spreading method has been studied more in detail with the help of tests
on sediments taken in the Lyon region.
