Directional drilling

[Lan123]

What is the maximum HDPE (High Density Polyethylene) pipe diameter that can be installed using the directional Drilling method? What is the maximum span between the two drilling stations? Are HDPE pipes suitable for below grade installation in cold climates. Application is water and sewage.

 

[77JQX]

I don't know the maximums, but I had installed 24" DR9 at 700 feet without special rigs. Supposedly, you can freeze water solid in HDPE without damaging the pipe, so I think it's probably a good choice for freezing climates.

 

[dicksewerrat]

Go to

http://WWW.trenchlessonline.com.

Find number for 3-4 large HDD contractors. Call them and explain your project. They will be able to help. One contractor I know did a 24 inch 2500 ft in Georgia a couple years ago. Since I work in Cured in place I don't have a good handle on max diameter for HDD. But i will ask around.

Richard A. Cornelius, P.E.

http://WWW.amlinereast.com

 

[BigInch]

An HDD could easily be installed below the freeze line, so you won't have a problem with that aspect of things. In cold climates, you would want all the pipe to be installed below the freeze line anyway.

Max diameter depends on the wall thickness as does the diameter of the cutting head and the length of the drill, so that the pulling force as the pipe is pulled into the drilled hole can be distributed over a large cross-sectional area to keep stress below maximum levels.

Besides soil properties and the curve geometry limitation of the drilled profile being gradual enough to keep bending stresses low, for which HDPE pipe would allow more curvature than steel, HDD is limited primarily by pull force; as the drilling rig must be able to supply that pull load, and the pull stress, which increases with friction.

Friction increases with length and diameter. Length is important because the sum of friction/ft during the pull increases linearly with length and it would also increases more or less linearly with the circumference of the pipe, [π] * D, which means linearly with the diameter * Pi. Once installed, soil load on the pipe would also be dependent on diameter, which would again impose a separate limiting factor.

I don't work with HDPE, so unfortunately I don't know what if any particular maximum practical limitations exist for HDDs with HDPE pipe, but I'm sure there are some. If you find out what they are, I and I'm sure a few of the rest of us would like to know, so please post them here.

Only put off until tomorrow what you are willing to die having left undone. - Pablo Picasso

 

[Lan123]

Thanks for all the comments. I did some google search and below is an interesting link that provide some information on the pipe dia., and, the bore length of directional drilling.

http://rebar.ecn.purdue.edu/Trenchless/secondpage/Content/HDD.htm#Diameter

range

 

[BigInch]

http://plasticpipe.org

has this chapter on HDD that looks good. Quite a bit of tech on design of a HDD crossing.

http://plasticpipe.org/pdf/chapter12.pdf

be sure to see the other chapters too.

Only put off until tomorrow what you are willing to die having left undone. - Pablo Picasso