Geosynthetic Reinforced Containment Dike Constructed over Soft Foundation: Numerical Analysis - Reinforced Soil Engineering: Advances in Research and Practice - page 281

Figure 3 Finite-element mesh.

Linear elastic material and plane strain mixed elements were selected to
model the dike and sand layer of foundation. The mixed element implemented in
SAC-2 has four nodes to represent the displacement and pore pressure. The
geotextile was modeled through the elastic membrane element to account for
the large deformations. The clays (Strata 1 and 2) were characterized using the
proposed anisotropic bounding surface elastoplastic model. The material
parameters for sand, fill, and geotextile are summarized in Table 2. The material
parameters for clays are given in Table 3 . Due to a lack of information on the
laboratory tests, some of the model parameters were estimated from the typical
values based on the sensitivity studies (Yue, 2001). Note that the same set of
parameters was used for the three soil strata.
The wick drain was modeled following the methods proposed by Poran
et al. (1988). A more comprehensive procedure of modeling was also proposed
by Amirebrahimi and Herrmann (1993); the essence of this method is to
transform the axisymmetric problem into its equivalent plane strain idealization
by conducting water flow analysis using the finite-element method. The two
simulations, which used different permeability coefficients but the same loading
conditions, were considered to be equivalent when the difference of the average
excess pore pressure, resulting from the two simulations at some particular time,
was within an acceptable range. The equivalent coefficients of permeability

Table 2 Material Properties of Sand, Fill, and Geotextile

Material Elastic modulus Poisson ratio Thickness

20 0 Sand 28,000 kPa 0.3

10 0 (3.3m) Stage I fill 14,400 kPa 0.3

10 0 (3.3m)

State II fill 28,000 kPa 0.3

Geotextile 1400 kN/m — 100mil