The results from 30 nonlinear finite-element analyses of undrained deep exc
avation in stiff clay are used to support the use of a new displacement fle
xibility number in multipropped retaining wall design. The analyses address
the effects of different initial stress regimes and various values of prop
stiffness for the internal supports to the excavation. It is demonstrated
that this flexibility number defines support systems that will displace to
the same maximum lateral wall deflection and will result in the same profil
es of vertical and horizontal ground surface displacement behind the wall.
It is concluded that, as it is these movements that must be controlled to l
imit the damage to adjacent buildings, structures, and services, the new fl
exibility number gives the engineer more confidence in assessing possible s
upport strategies to a given problem at a given site.