<p>There are significant
problems during construction to establish an adequate foundation for fills
and/or subgrade for pavements when the natural ground has low-bearing soils.
Geosynthetics such as geogrids, geotextiles and/or geocells could provide an
alternative, less costly in time and money, to establish an adequate foundation
for the fill and/or subgrade. There is extensive evidence in the literature and
on DOTs practices about the suitability of using geotextiles in pavements as
separators. Previous studies have also shown that the use of geogrids in
flexible pavements as a reinforcing mechanism could decrease the thickness of
the base layer and/or increase the life of the pavement. In this study,
analyses of selected pavement designs using Pavement ME, while considering
geogrid-enhanced base or subgrade resilient modulus values, showed that
geogrid-reinforcement, when placed at the interface between subgrade and base,
did not produce significant benefits, as only a modest increase in pavement
life was predicted. In addition, parametric finite element analyses were
carried out to investigate the potential benefits of placing a geogrid at the
base of a fill over a localized weak foundation zone. The analyses showed that
the use of geogrids is beneficial only when: (a) the stiffness of the weak
foundation soil is about an order of magnitude smaller than the rest of the
foundation soil; and (b) the horizontal extent of the weak foundation soil is
at least 30% of the base of the embankment foundation. The largest decrease in
differential settlements at the surface of the fill, resulting from
geogrid-reinforcement, was less than 20% and, therefore, it is unlikely that
the sole use of geogrids would be sufficient to mitigate differential
settlements. Based on previous studies, a geocell mattress, which is a
three-dimensional geosynthetic filled with different types of materials, could
act as a stiff platform at the base of an embankment and bridge over weak zones
in the foundation. However, given the limited experience on the use of
geocells, further research is required to demonstrate that geocells can be
effectively used instead of other reinforcement methods.</p>
| Identifer | oai:union.ndltd.org:purdue.edu/oai:figshare.com:article/17152706 |
| Date | 19 December 2021 |
| Creators | Eirini Christoforidou (11819009) |
| Source Sets | Purdue University |
| Detected Language | English |
| Type | Text, Thesis |
| Rights | CC BY 4.0 |
| Relation | https://figshare.com/articles/thesis/Use_of_geosynthetics_on_subgrade_and_on_low_and_variable_fill_foundation/17152706 |
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