315mm Sewer Replacement

We were working with DKS Utilities Ltd on this project in the middle of the Imphal Barracks within the Military Garrison in York, on behalf of Severn Trent and The Ministry of Defence. A section of the main sewer was blocked and causing problems - We were brought in to replace the broken section., but this wouldn't be as straight forward as simply installing a new main.

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Because of the specific location of the sewer, it would have been an excessively expensive, complicated and technically challenging task to route any replacement to a suitable connection point of the existing main; this would have necessitated the destruction of mature trees, road surfaces and footways. It was decided that we would use the broken section of the existing drain to get under the tree lined road and into a chamber in which the new section of main could be connected to the existing one.

 

This required some specialised works, including deep excavations and excavation support which were completed and overseen expertly by DKS's on site engineers,  From our point of view, it would involve drilling to a very specific depth at an equally precise angle in order to run up the existing pipe - we would then push the rods up this pipe until we reached the chamber, use this point to attach a reaming tool and while trailing rods, cut away the old clay pipe and pre-ream the pilot bore. We decided to push back up the borehole with the head rather than a forward reaming tool to ensure we were working within the same borehole, following the completion of a further reaming pass, the new 315mm MDPE section was pulled into place. 

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