Page 108 - Numerical Analysis and Modelling in Geomechanics

WAVE-SEABED-STRUCTURE INTERACTION 89

Table 3.2 Input data for case study of wave-seabed-caisson interaction.

(b)). It is also noted that the maximum pore pressure occurs at section 3, which is
the intersecting point of caisson and rubble mound. Since sections 2, 3 and 4 are
the three most dangerous regions for most marine structures, only results at these
three sections will be discussed below.

Effects of cross-anisotropic soil behaviour
Poisson’s ratio (µ ) describes the strain in one horizontal direction caused by the
xx
strain in another horizontal direction normal to the first direction. On the other
hand, Poisson’s ratio (µ ) also describes the strain in the horizontal direction
xz
caused by the strain in the vertical direction. Their effects on the wave-induced
pore pressure are discussed in this section.
Figure 3.19 shows the vertical distribution of the wave-induced normalised
pore pressure (p/p ) at different sections for various values of Poisson’s ratio
o
(µ ) in coarse sand and fine sand, respectively. Generally speaking, the wave-
xx
induced pore pressure increases as µ xx increases. The figure indicates that
the effects of µ are more significant at section 4 in fine sand. Compared with
xx