Why are trench dams important in pipeline construction?
When ground water invades a pipe trench, it will flow down the slope, creating an under ground river. This flow erodes the back fill and creates voids. When a load passes over the pipeline, it could cause a collapse of the fill.
What methods have been used prior to the introduction of Ripley’s Dam?
Clay has been packed around the pipe or concrete has been poured or formed in the pipe envelope. Clay and concrete fail to make a seal. Clay is a poor bedding material and concrete places an unnecessary load on the pipe.
How often should dams be placed on the pipe run?
This is a good question. One agency uses a rule that places ten percent of the pipe run in the numerator and the trench width in the denominator. The quotient is the number of dams in that run of pipe. The engineering inspector on the job can be the best one to call for the installation of dams.
What do contractors think of Ripley’s Dam?
Contractors like the ease of installation. If they are faces with a specified concrete dam, they will aske for Ripley’s. If they have a dirt dam, they might ignore it. One engineer commented, “If I had a dollar for every dirt dam not installed, I would be able to retire.”
Are the dimensions of the Ripley’s dam adequate?
Yes. The purpose of the Ripley’s dam is to stop the flow in the pipe envelop, the area of the high hydraulic conductivity. This allows the soils to function as a sponge and hold the water. Ripley’s Dam gives Darcy’s equation an opportunity to function.
Will Ripley’s Dam hold up to cold weather?
Yes. The dam is made of ABS (Acryonitrile Butadine Styrene) that performs acceptably in cold temperatures. ABS has good corrosion properties as does the flexible adapter.