Nantwich Manhole Culvert

The Project

The chamber was constructed on the grass verge adjacent to the towpath. ​

Due to the remote location all materials and plant had to floated to/from site including an 8t digger to facilitate lifting the manhole rings and trench box.​

As the exact route and depth of the culvert were unknown, trial holes were excavated to locate and measure it. Access required the removal of a bench and concrete pad, both of which were reinstated upon completion.​

​

Once the culvert was identified, a trench box was installed to support the excavation whilst works took place. Due to the culvert’s condition, the design was revised to minimise the risk of collapse. Excavation was limited to approximately halfway down the culvert barrel before constructing the concrete base, which was reinforced with mesh to provide additional structural support.

Following completion of the base, precast concrete manhole sections were installed using an excavator, along with the cover slab. We backfilled around the outer edge of the chamber with pea gravel to eliminate any air gaps that could cause ground subsistence. ​

​

The manhole cover was then fitted, incorporating a minor design amendment agreed with the CRT engineer, using a concrete surround in place of brick.