The unexpected ground conditions caused the pausing operation of a tunnel boring machine working on Scottish Water’s £2.5M Stonehouse sewer project.
In order to assist divert storm waters to a sewer with greater capacity, a new sewer pipe is being installed in Stonehouse.
With the cooperation of Caledonia Water Alliance, comprising Morrison Water Services and Aecom, the flood prevention project is being delivered for Scottish Water by its alliance partner.
Following the tunnel boring machine (TBM) ran into solid rock, tunneling work below a local primary school’s grounds and pitch had to be stopped early last month.
Scottish Water stated the TBM ran into unforeseen ground conditions after it commenced its drive.
The water supplier is now reassessing its approach to installing the new sewer pipe, which follows a route across the school car park.
Benefiting a larger tunneling machine or using an open cut method, may be one of these approaches.
According to Scottish Water in an update on its website: “We will now carry out a detailed assessment and review and will provide everyone, including the school, with an update as soon as we have more information.”
Due to the safety of the tunnel shaft area, the review is carried out, and work is going to focus on pipelaying in a different area.
Considering that a delay has occurred in the tunneling process, the determined date for completion of this project is now scheduled for autumn/winter 2022 instead of this summer, while work on the overall scheme started last October.