Directional Drilling sewer pipe
Directional Drilling sewer pipe
(OP)
I was wondering if anyone had any experience with directional drilling sewer pipe.
I'm very interested in doing a small project (150metres) this way. I heard you can use a conintuous length of PE pipe and fuse the connections as you go to keep adding length.
I would like to hear any opinions if anyone has done this kind of placement.
Thanks
I'm very interested in doing a small project (150metres) this way. I heard you can use a conintuous length of PE pipe and fuse the connections as you go to keep adding length.
I would like to hear any opinions if anyone has done this kind of placement.
Thanks





RE: Directional Drilling sewer pipe
We had a very steep cross slope, adjacent to a busy highway, which they did not want to alter much to allow equipment access. This lead to the DD. Unfortunately, the pipe was designed near minimum slope, and we ended up with some reverse flow near the end due to the drilling technique. A section of pipe at the end had to be removed, and a manhole was shifted to be avoid any connection type issues.
I would say it is feasible, as long as your design allows for some change in slope, and that your slope is definately above minimum.
RE: Directional Drilling sewer pipe
RE: Directional Drilling sewer pipe
In talks with some collegues, I found out the same thing. The HDPE pipe comes in rolls so it is very hard to lay it flat even when directional drilling. So it is, like you say, only should be used in high slope areas.
Its amazing, when directional drilling is cheaper than conventional. Good to see technical advances such as these.
RE: Directional Drilling sewer pipe
RE: Directional Drilling sewer pipe
RE: Directional Drilling sewer pipe
RE: Directional Drilling sewer pipe
I didn't really get rconner's point, but HDPE is suitable for use in directional driling for pressure pipe - water mains for example. The drilling fluid would normally be bentonite or polymer.
Fot trenchless installation of sewers the required accuracy can be achieved with pipe jacking or micro-tunneling. In this case due to the heavy duty pipes needed open cut is usually less expensive if possible.
RE: Directional Drilling sewer pipe
Richard A. Cornelius, P.E.
WWW.amlinereast.com
RE: Directional Drilling sewer pipe
RE: Directional Drilling sewer pipe
At some degree of severity, I believe some sag “defects” have been implicated in eventual sedimentation/formation of slimes, accompanying generation of hydrogen sulfide, various blockages, and maybe even some subsequent overflows with potentially now quite serious contemporary ramifications (at least in some areas). As a consequence, I also believe that for whatever reasons at least some jurisdictions/authorities are attempting to enforce quite stringent sag inspection criteria, at least for new construction and even on gravity sewers laid to slight/quite flat grades, e.g. in some cases ostensibly allowing no more than ½”-5/8” of standing water.
I suspect those (at least those carefully studying the issue) who advocate installation of plastic (very lightweight, slick on at least the outside) gravity pipes by HDD, or maybe even by other means in deep wet, high-ground water areas are doing so by suggesting relaxation of the sag criteria, a substantial increase of design sewer grade, or both. While I am not knowledgeable enough to gauge the long term effects (if any) of the former practice, I know the effect of the latter increase of the design grade can be that one gets quite deep in the ground quite fast on the way to the plant (I believe not generally helpful when trying to serve a large area with gravity pipes!)
I have incidentally been a proponent of trenchless construction, as another tool in the toolbox, for about 25 years. I have therefore watched the rapidly developing “technology” as closely as I could. While I have great respect for the ingenuity/value of some “contractors” and developments of “technology”, I have even more respect for the laws of physics/geo-physics and I believe some caution is in order lest over-selling without detailed education set the industry back some in this area.
RE: Directional Drilling sewer pipe
Ted Dimitroff - President
Trenchless Flowline, Inc.
7850 East Highway AB
Columbia, Missouri 65201
573-449-6186 - office
573-449-1031 - fax
573-268-2294 - cell
tdimitroff@trenchlessflowline.com
RE: Directional Drilling sewer pipe
First, it is important to understand the distinction between directional boring and underground boring.
Gravity sanitary sewers cannot tolerate 'porpoising' or humps in the pipe. With conventional horizontal drilling, a strait, concentric bore cannot be assured due to rocks, lack of precise control, ect. This is why open trenching is the method of choice. However, in the case of highway or stream crossings, a trench may not be tolerated. Enter directional boring.
For example, say we wish to route a gravity sewer pipe under a highway. With a directional bore, two large pits are dug on either side of the highway. Next, a steel pipe sleeve is driven between two target inverts. The soil on the inside diamter is extruded in this process. The PVC sewer main is placed inside this sleeve. The PVC pipe is maintained concentric inside the sleeve using special hardware.
Directional boring is expensive due to high mobilization cost, tight concentricty tolerances and expensive special equipment. I completed a 50 ft section for $30,000.00. Most of this was for mobilization.
Hope this helps.
RE: Directional Drilling sewer pipe
by "directional boring" are you referring to microtunneling or pipejacking?