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发表于 2007-9-27 17:31:25
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来自 上海闸北区
As discussed in the Limit Equilibrium Fundamentals Chapter, SLOPE/W is
formulated on the basis of total forces. The unit weight consequently needs to be
specified as the total unit weight.
SLOPE/W allows for a separate unit weight above the water table, but use of this
parameter is seldom necessary.
First of all there is the capillary zone where S is 100% and the unit
weight therefore is the same above and below the water table in the capillary zone.
Secondly, factor of safety calculations are not very sensitive to the unit weight. If
the slice weight increases, the gravitational driving force increases, but the shear
resistance also increases because of a higher normal at the slice base, and vise
versa. Therefore, defining different unit weights above and below the water table
usually has little effect on the resulting factor of safety.
一句话,安全系数对重度不敏感。 |
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