Figure 5. Three-Dimensional FEM (3-D FEM) modelling of a section of Conlay underground station
Figure 6. Tunnel breakthrough at Chan Sow Lin
Station.
of computer and software capacities, many of
the analyses and design methodologies not
previously feasible nor possible 10 years ago are
now commonplace, such as the three-dimensional
(3-D) finite element method for soil-structure
interaction problems.
There is a saying in engineering designs where
the term factor of safety is rather a factor of
ignorance; only to be used when one is not sure of
one’s design. While this statement is not entirely
true, particularly in geotechnical engineering where
much uncertainties exist in the ground, it does
remind engineers that unnecessarily conservative
and “overly” safe designs are not the way to go.
These often result in an environmentally unfriendly
design; one that requires more resources and
materials and ultimately costs more. Continuous
research efforts across the years internationally
and the advancement of computing resources
play a role in reducing uncertainties with regards
to deformation mechanisms. However, it is quite
often that the industry is contented with existing
older methods due to familiarity, thus becoming
slow to take up new approaches.
At this stage, it is also critical to point out that
one can go to the other extreme, treating results
from these sophisticated analysis tools as an
absolute truth but forgetting that it is often only
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