Bore Under Creek 1

[Civilychallenged]

Has anyone here experienced boring underneath a creek? Were there any major difficulties/problems?

We want to run a 4" Sewer Force Main underneath an exist, flowing creek (not a huge amount of discharge)...only about 10 feet wide and under 1ft deep...90% of the time. We are talking with the Army Core to obtain permission.

We are also looking at hanging from a bridge, but for right now I am to design the bore.

Let me know...

Thank yahll

 

[yogibear1]

Are you talking about jack and bore or directional drilling? Both are performed routinely in our area of west central Florida. Most recently we did a 24 inch directional drill under a local river. I know the route was quite deep and had problems when sticky blue clay gummed up the works. The lesson learned there was about insufficient geo-tech information, esp at the depth of the bore.

From my experience with the USACOE and permitting I would hang it from the bridge assuming there is adequate structural support to do so, and no other negative factors. Otherwise, I'd use long span pipe set on independent piles either side of the creek. If you do this you will have to place an ARV on the high point of the pipe to let the air out.

 

[francesca]

I recently worked on a project under the direction of a highly experienced (former City Engineer, nearing retirement) engineer that involved running a 8" sewer forcemain under a continuously flowing creek in northern Middle TN.

The creek is over 50' wide and under normal flow conditions, is approximately 6' deep. We used an open cut method to lay the forcemain. Further, while the majority of the FM was PVC, the section under the creek was Ductile Iron.

In TN we had to apply for an Aquatic Resourse Alteration Permit (ARAP), and there was a General Permit for creek crossings (the TN general permits expire on July 1st and they're no longer issuing approvals under them). The Corps of Engineers permit only applied on this particular creek because it is near the dams on the Tennessee and Cumberland Rivers and the Corps has a flowage easement to an elevation higher than the creek bed elevation.

 

[francesca]

Sorry, I forgot to mention that we maintained a minimum of 3' of cover over the forcemain.

Boring was considered for this project, but open cut was deemed cheaper.

The project has been completed and the contractor did not have any trouble, even though the banks of the creek are very steep and about 15'-20' high.

Erosion control is obviously a challenge in open cut situations and I haven't been out there to see how well the contractor achieved this. NPDES Phase II has only recently been implemented in my area, so contractors are usually pretty lax on erosion control.

 

[Civilychallenged]

Did you divert the creek or dam it to do the open cut?

 

[francesca]

Would you believe me if I told you that our drawings didn't specify this?! It would've been a significant engineering undertaking to do either, so my guess would be that they did the open cut in sections, diverting the stream around the work area.

I believe our decision for open cut was because there is a significant amount of rock in the area. If there isn't a period during which your creek is either dry or has low flow, it might be cheaper to bore.

 

[rconner]

Ductile iron pipe offers a great deal of versatility, security, and decades of usage/experience for such installations. In some cases standard, push-on restrained or unrestrained joint pipes can be installed in a trench with pipeline profile that should remain undisturbed and below future scour depth of the waterway. With this type of piping and joints it is generally also best if flow can be diverted or temporarily dammed, and the joints assembled and firmly backfilled "in the dry".
"Ball joint" ductile iron piping on the other hand offers great strength, damage resistance for unseen marine conditions, extremely flexible restraint that does not necessarily require dewatering or flow diversion, and this specialized type of piping often allows rapid and secure installation in much lesser conditions than standard pipes. Ball joint pipe can also be installed by a wider variety of methods including pulling/dragging from banks, float and sink, installation from barge ramps, installation by divers, just assembled like other pipes, and/or is also sought out in general applications for increased seismic movement/settlement abilities etc. (all though at increased material/manufacturing costs for this more specialized pipe).
In the last 10-15 years, there have also been increasing applications of contemporary boltless, flexible restrained joint ductile iron pipes (with sufficiently strong, flexible, and low profile restrained joints available from some manufacturers) for pulled horizontal directional drilling, as well as these or other specialized joint ductile iron pipes designed for trenchless pipe jacking, microtunneling, and other pipe pushing applications. While the strength, toughness, and flexibility of ductile iron pipe is perhaps equally advantageous in these out-of-sight installations/conditions with unknown bedding represented by underground pulls or pushes, it can be be overall less costly to "open cut" in some cases (as another poster has stated), even with the more expensive ball joint piping.
There is more detailed information available from the Ductile Iron Pipe Research Association (dipra.org) and ductil iron pipe manufacturers with regard to such specialized applications.

 

[daddymem]

We have just recently done two projects involving similar situations.
One project had two different solutions. The contractor did a directional drill under a box culvert located in a causeway crossing a pond. This was about 10 feet deep and 100 feet in length using a 6" HDPE pipe. The contractor did a pipe jack under an active railroad track. This was about 8 feet deep and 160 feet in length using a steel casing.

In the other project, the contractor did a directional drill under a small stream in order to keep outside of the no-disturb buffer. I don't have other specifics since this was not my project.

All three applications involved sewer force mains and all three went well, the directional drilling went the smoothest and had the least impact on the surroundings. I should point out that all cases involved high groundwater so the jacking was a bit messy. We explored hanging the pipe on the box culvert but there were issues with insulating the pipe and concerns with kids tampering with the pipe so below ground was the chosen solution.

I ain't never seen a hearse with a luggage rack.-GS

 

[Pulpboy]

After performing about 1000' of 3 directional drills I can say the process is pretty painless. I would recommend that on any pipe as large as 4" or more I would buy the lengths of straight pipe and set up a fusion machine and expert. They can join a bunch before you pull or if space is limited they can fuse it while you pull. The coils/rolls are very cumbersome and unless you have the proper equipment and a braking mechanism they can unravel and cause a lot of headaches. We chose directional drilling since the ground was so wet / unstable and shoring the entire length was not practical. Even the couple spots we did dig & shore for connections was a pain due to water infiltration.