Abstract:
A nonlinear, plane-strain, dynaaic finite element method of
analysis computer program is developed to study the
interactive behaviour of underground structures. Static
problems can also be solved without loss of efficiency. An
extensive description of the analytical models used in the
code is given.
A planned scheme of analyses was performed to study the
dynamic response of soil without buried structure and the
interactive response of a buried structure subjected to
impulsive loading on the surface. Base conditions of rigid
and semi infinite cases were investigated to study their
influence on the response of the system. A parallel series
of nonlinear static analyses was performed for the maximum
magnitude of the shock loading.
An optimum position of the structure in the soil was found
giving minimum moments in the structure. For rigid base
case, proximity of the structure to the base severely
affected the system response. Elimination of the reflected
wave actions by use of viscous base yielded that no specific
advantage in load sharing of the structure can be gained for
high depth of burial. Inadequacy of the presently available
recommendations for a unique dynamic magnification factor
was proved by comparing the,results of parallel dynamic and
static analyses.
