The Saturated Only soil model is very useful for quickly defining a soil region that
will always remain below the phreatic surface, but it should not be used for soils
that will at some point during the analysis become partially saturated. If this
happens, the model will continue to solve but you will be saying, in effect, that the
unsaturated zone can transmit the water at the same rate as for the saturated soil.
This will result in an over estimate of flow quantity and can result in an unrealistic
water table.
如果在存在非饱和的情况下使用饱和材料,则会计算出不真实的水位线。所以这个算例中将心墙设置成完全饱和计算结果没有意义。