31 Aug 94
Crack plot at day 163 of the middle wall half of the chamber monolith model
placement case, while compression is being relieved
point from the surface (Figure B-24) shows how the
for the other cases. Since this is a time-history analy-
ambient placing scheme has become the more critical
of the three cases.
sis and the stiffness matrix is reformulated with each
step based on strain state of the previous step, the
relief of stresses occurring has an impact on the
(a) The reason for the behavior exhibited at the
results at later times in the analyses, hence the lower
stresses for the ambient placement case at day 200.
the beginning of the time history is looked at more
closely as shown in Figure B-25. As can be seen, the
(b) Finally, Figure B-26 shows a time history of
initial stress history of the three cases shows that the
the maximum principal stress at a point in the wall.
ambient placement case produces tensile stresses
For this point the ambient placement case controls,
almost immediately while the other two cases go into
but the stresses are relatively low and therefore are
compression first. It is at these early times that the
highest rate of creep is occurring. Therefore, tension
not a major concern.
at early times is being relieved for the ambient