Performance of Geosynthetic Reinforced Soil Wall and Reinforced Earth Wall Subject to Blast Loading: Experimental and Numerical Study - Reinforced Soil Engineering: Advances in Research and Practice - page 373

Table 6 Manual Setting Values for Iterative Procedure Used in Analysis

Parameter Manual setting value Default value

Rayleigh damping coefficient a 0.01 0

b 0.01 0

Newmark time integration factor a 0.25 0.25

b 0.5 0.5

Viscous boundary condition C1 2 1

C2 2 0.25

pressure of 180 kPa, and MD5-E2 with peak pressure of 130 kPa. The blast
loadings were assumed to be a plane compressional impulsive wave imposed as a
time-varying pressure on the whole vertical front of the RS wall, as shown in
Fig. 17 . The blast pressure-time history acting on the boundary of the reinforced
soil wall was determined by means of approximate method based on the
empirical charts and equations proposed by Bulson (1997) and Baker (1983).
The computation time of the dynamic analysis was continued for 40 ms
even though the duration of blast loading was only 15ms. This is to ensure that
the system returns to an equilibrium state after the blast. A special type of viscous
dynamic boundary conditions was imposed on the left and bottom end of the
FEM model to account for the fact that in reality the soil is a semi-infinite
medium. This viscous boundary can absorb the increments of stresses on the far
end boundaries caused by dynamic loading, which would otherwise be reflected
inside the soil body and disturb the results. In the dynamic analysis, the settings

Figure 18 Typical deformed mesh of the model after the blast loading (scale up 20
times).