Introduction
HBT were approached by a Thames Water Framework contractor to assist with the installation of a 150mm foul pipe beneath an existing carriageway and down the embankment of a railway line, as part of a housing development.
During our site visit, it became clear that access and site constraints posed significant challenges. There was a twin-track railway line in close proximity, along with restricted access to the downstream Thames Water connection manhole.
The client requested that we liaise directly with Network Rail. To comply, HBT undertook the necessary approval process in line with Network Rail procedures.
Augerboring
Objective
HBT were awarded the installation of four shots (three lengths of clay and one shot of 244mm steel, subsequently lined with 180mm OD SDR 11 threaded pipe [150mm ID], with the annulus grouted).
Due to restricted access at the downstream Thames Water connection manhole, a sacrificial steel sleeve was required, and the biscuit had to remain in situ. As part of settlement and heave calculations for Network Rail, HBT elected to use the BM400 rig, which incorporates a semi-closed face system to minimise potential settlement when boring adjacent to railway lines.
The Challenge
Once the settlement calculations had been completed and submitted to Network Rail for approval, works commenced on site. The works involved the installation of three lengths of 50 metres of clay jacking pipe, and one length of 244mm and 150mm NE pipe, 12 metres in total, for the final connection.
All works were completed on programme and within budget.
“We were struggling to see how the works could be
completed with all the site constraints. HBT came up with a solution, took the
lead with Network Rail, and nothing was too much trouble.”
- Paul Taylor
For more information please contact us on 0845 388 3325 or 07879 624900
