Civil and Environmental Applications of Geosynthetics - Reinforced Soil Engineering: Advances in Research and Practice - page 4

Figure 1 Geosynthetics in soil reinforcement: (a) wraparound wall; (b) modular-block
wall; (c) embankment over soft foundation.
applied considering possible strength reduction of geotextiles by installation
damage, creep, chemical and biological actions. Geotextiles may degrade by
exposure to ultraviolet rays, high temperature, oxidation, and hydrolysis (when
the environment is highly alkaline), but the effect is minimized when buried in
soils.
The frictional behavior of a geotextile with site-specific soil must be
determined by direct shear tests. Although the ASTM standard specifies a direct
shear box with dimensions of 30 cm by 30 cm, the box with a plane area of 10 cm
by 10 cm would be adequate for geotextiles. Pullout tests have been proposed in
the last few decades for determining the anchorage capacity of geosynthetics;
such tests are not relevant in determining the design parameters because they are
subject to scale and boundary effects.
For embankments and dikes constructed over a soft foundation that lacks
bearing capacity and global stability, a layer or more of geotextile is laid at the
base of the embankment. Vertical wick drains of geosynthetic composites or sand
drains may be used to accelerate consolidation of the soft foundation. Geotextiles
have also been used in conjunction with the underwater sand capping of
contaminated submarine sediments. In these applications, the seam strength may
dominate the design.