Western Power Distribution Under-Track Crossing Installation at Weston Super Mare21st September 2020
After securing a contract with Western Power Distribution (WPD) to fulfil an Under-Track Crossing (UTX) installation in Weston Super Mare, our Enable consortium was required to fulfil the requirements of the job. Thus ensuring that our streamline internal process was executed to its desired effect. With BCM leading the construction side of the project, Crewit providing experienced operatives, Equate providing qualified engineers and CHS supplying the plant and materials.
Because of our civils experience providing expert railway interface and operating our Principal Contractors License (PCL), we were contracted by WPD to conduct these works and manage the Network Rail’s Asset Protection and Optimisation teams (ASPRO) who provide expert railway assistance and support to the public who are planning activities on or near the railway.
We were tasked with the job of installing new cable routing from the feeder grid for 2 separate substations. With one situated at Warne Road and the other at Bourneville Road Playing Fields. This required the positioning of the thrust and the construction of the reception pits to be outside of the NR boundary fences and therefore on private land. Western Power Distribution efficiently obtained necessary consent from the third party before the UTX installation work began.
We were continuously auguring under an operational railway which meant track monitoring was undertaken continuously.
Once the shaft pit locations were marked out by our setting engineer in accordance with AFC Design and the permit was completed. The excavation began via a dig and push method creating one drive pit of 4x4m and 3.4m depth and a receiving pit of 2x2m and 3.4m depth. RC thrust walls were then constructed in the dive pits to allow the guided auger boring equipment to install the UTX.
Form work walls were constructed with shuttering ply, timbers, and reinforcement A393 mesh. 2 sides needed to be constructed with 2 of them being 300mm thick and the other 2 being 500mm thick. Once the concrete was poured in the into the form work walls and been tested to confirm that the RC walls within the pits achieved the correct required strength in line with the design.
Once our Equate engineers confirmed the set out and mark line gradient of the bore, and the permit to drill had been signed, we commenced with the auguring process. A 13t machine was used to load the sacrificial steel sleeve with a flight auger and together with the cutting head fitted lower. The cutting head is connected to the rear of the pilot rod and flight auger connected to the drive of the auger machine. Boring then commences with the auger being filled.
The sacrificial steel sleeve was being pushed into the ground whilst simultaneously rotating the augers, ejecting the pilot rod into the exit shaft where disconnected. The spoil from the augers were discharged into the drive shaft and loaded into skips and removed from the pits with use of our 13t machine. The spoil removed will be closely monitored to the volume of the sleeve installed. Allowing for bulking. The expected increase was for it to be around 15-20%.
A suitable machine was used to load a sacrificial steel sleeve with a flight auger and lowered under the supervision of a qualified slinger signaller and banksman. Additional sections of sacrificial steel sleeve are connected by welding each join. The flight augers are then rotated and retracted to drive shaft clearing loose spoils remaining inside the sacrificial steel sleeve. As each section of flight auger arrives in the drive shaft they are disconnected and lifted to the surface. On Completion of Auger Boring. The auger machine master frame & ancillary items will be removed from the shaft with the use of a 13t machine.
Please watch our video of the work that was done here:
- Liverpool Street Station Platform Extension GRIP 5-8 Design & Build Copy 13th November 2020