Pre-cast concrete pipe is delivered in precast units that are ready for installation. Box culvert sections can be used for applications where square or rectangular shapes may be more beneficial, such as low clearance areas, pedestrian tunnels, etc.Ĭoncrete pipe is not suited for applications having high internal pressure. Jacking and microtunneling applications where pipe with high strength is needed for the jacking forces. For more detail information, please contact the manufacturer, pipe association or your consulting engineer.Īll information presented was provided by the various pipe associations or manufacturers. As always, the information presented is intended to provide just a preliminary glimpse at the different pipe on the market. Some have changed in the four-and-half years since we last conducted this round-up, others have not. To help you out, Trenchless Technology once again contacted pipe associations and manufacturers of the eight pipes typically used in trenchless projects to point out what their particular conduit offers. No matter the circumstance, what you need is a primer on what the different pipe varieties offer. In some instances, the options are limited to what the client specifies or the material the pipe is intended to transport and in other instances, the sky really is the limit. I guess that may or may not be the case now, depending on lengths involved and conditions etc (I think far below the water table does favor MT).From oil and gas projects to sewer work and every trenchless application in between, pipe selection is an important aspect of the planning process. and particularly for short crossings were generally higher, and in some cases a whole lot higher for MT. Not surprisingly, if all else was equal and work was above the water table, I think the installed MT costs per foot etc. As previously mentioned microtunneling (MT) involves newer technology/rather complex and some would argue more sophisticated equipment (I think early machines a quarter century ago went for about a million clams apiece, with mobilization for pushes a big part). While not purporting to be an expert in the process, I think construction cost estimating particularly for such specialized pipeline methods is a complicated business, and results can vary widely with a whole lot of factors, probably not the least of which is the locale (including soil and groundwater conditions) and the availability of the specialty contractors(or subs), equipment and expertise to do the work in the area involved). There are actually different variations or flavors of both. RE: Difference between Jack and Boring and Microtunneling rconner (Civil/Environmental) 23 Jun 15 20:43
Microtunneling would be preferred over jack-and-bore in areas of high water table unless the push and receiving pits have pumps running to draw down the water level during the work to keep the pits safe for boring and assembling the pipe. If iron pipe is used, it should be polywrapped. Plastic pipe is popular for this, but iron pipe can also be accomodated. Many times they overbore the hole and use bentonite drilling mud, then when they pull the head back through the hole they drag the new pipe with a cable. In microtunneling, pits are not always needed and the contractor can steer the cutting head horizontally and vertically to the receiving location. Contractor installs what looks like a small locomotive on rails with a rotating head to auger and push a casing pipe through the ground to the receiving pit.
Jack-and-bore is used for horizontal pipe installations (beneath highways, rivers, etc.) where a push and a receiving pit are excavated.
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