Numerical Modeling: An Efficient Tool for Analyzing the Behavior of Constructions - Multiscale Geomechanics: From Soil to Engineering Projects - page 301

306 Multiscale Geomechanics

Figure 9.26. Comparison between experimental results (data from Fioravante [FIO 02]) and
the model's prediction [DAG 08] of a constant normal stiffness direct shear test (CNS), on
Toyoura sand ( D r = 90% ), rough and smooth aluminum plates with R n =0.13 and
R n =0.01 , K =1,000 kPa/mm, δ = τ s /σ n

the mechanisms of load transfer along the pile and can be compared with results of the
numerical modeling (see Figure 9.28).

We note that the non-linear behavior of the sand is well represented by the soil and
the interface models. The amplitude of β = τ s /σ v0 decreases with depth. A series
of parametric studies can highlight the parameters that influence the mechanisms of
load transfer from the pile to the granular media. Besides the interface roughness,
the soil state parameters play a very important role in the response of the pile. Thus, the
influence of the density of the surrounding soil and the length and the roughness of the
pile were studied. The influence of a soil state (density, initial stress) can be grouped
into a single state parameter, corresponding to the position of the point relative to the
critical state, which can be characterized by the ratio p 0 /p c 0 . This state parameter is
useful for quantifying the distance to the critical state line and the level of dilatancy
and, consequently, the shear mobilization. This notion of state parameter is also used