Measuring Uplift Pressures in Flowing Relief Wells

It is a common practice to try to measure uplift and pore water pressures under dams by inserting a packer with a pressure gage into a flowing relief well or foundation drain. The purpose of this Technical Note is to demonstrate that measuring uplift pressures in flowing relief wells and foundation drains by this method results in indicated uplift pressures that are higher than those existing when the relief well or foundation drain is allowed to flow freely. The result is a "false high" measured uplift pressure. This can be significant if the dam is being considered for stabilization as demonstrated by the [cited] case history. (author intro)

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