Throughout July and early August, work has been proceeding to construct the new earthworks and laying of new drainage in fields on both sides of the A46.
Overview
Throughout July and early August, work has been proceeding to construct the new earthworks and laying of new drainage in fields on both sides of the A46. Traffic management and barriers are still in place on the southbound off slip and northbound on slip to create working room close to the two slip roads.
By the end of July, approximately 66,000 tonnes of material had been imported to site to construct the new northbound on slip, and the area which will be the new western gyratory of the signal-controlled roundabout. The earthworks for these two areas are now complete. The imported material is now being placed alongside Stoneleigh Road heading towards Finham Brook and will be continued in the weeks ahead.
Earthwork operations have also been continuing the east side of the junction in order to construct the new Stoneleigh Rad east approach and the eastern gyratory. The new southbound off-slip earthworks have been previously completed and the first stages of road construction is taking place. This involves the laying of a hardcore material, known as “capping” to form the foundation of the road.
Cadent Gas continued diverting a major gas main on Stoneleigh Road and Dalehouse Lane. The three-way temporary traffic signals around Dalehouse Lane Roundabout were in place twenty four hours a day, seven days a week throughout the process. All work was completed by 16th August and the traffic signals removed.
Progress to date
Cut/Fill Earthworks Activity – New Northbound On Slip and West Roundabout Gyratory
Importing of earth has been proceeding throughout July and early August. This is placed into the new roundabout and slip roads area in layers and then compacted with a roller to ensure it is of solid construction. Regular testing of the layers is undertaken to check the level of compaction of the layer achieved meets the threshold that the design requires – typically 95%.
The fill is profiled into a slope which will form the permanent embankment, and this will eventually be topsoiled and planted/seeded. The new northbound on-slip and western roundabout gyratory have been completed to the required finished level. The fill operation is now continuing down from the new gyratory area towards Finham Brook.
Figure 1 shows the new northbound on-slip embankment slope. Figure 2 shows the ongoing fill operation heading down towards Finham Brook.
Figure 1 – Earthworks Fill Operations – New Northbound On Slip Near Existing Slip Road
Figure 2 – Earthworks Fill Operations (From Existing Stoneleigh Rd West Looking Towards new Northbound On Slip)
Cut/Fill Earthworks Activity – New Southbound Off Slip and East Roundabout Gyratory
As with the northbound on-slip and western gyratory, this area is being filled to bring the area up to the required level for the eastern roundabout gyratory. The method of construction is through the same layer installation process described previously. In this location, it has been necessary to construct a stronger embankment alongside the existing southbound off-slip to allow the existing southbound off-slip road to remain open whilst the works are ongoing. The slope can be seen in Figure 3.
Figure 3 – Earthworks Fill Operations – New Southbound Off Slip Slope
Cadent Gas works on Dalehouse Lane
As the new road alignment for Dalehouse Lane will impact on an existing gas main, it was necessary to divert it before the main roadworks commenced. This diversion work continued throughout July and early August and had three-way traffic signals in place twenty four hours a day, seven days a week. The diversion was successfully completed, and the road reinstated by 16 August, at which time the three-way signals were removed and the roundabout opened to traffic.
Ongoing drainage works
Work has now commenced on installing new storm drainage on the new slip roads, particularly the northbound on-slip road. This involves excavating trenches, laying new pipes, and then backfilling. New manholes are also being constructed.
Road construction works
Work will continue on the installation of the new road construction on both the new slip roads. This will include laying a compacted hardcore foundation (termed “capping) along with a granular sub-base. Bituminous layers will then be constructed which will form the final road surface. Figure 4 shows the capping already installed on the new southbound off-slip.
Work to install new kerbing is also planned to take place before the end of August.
Figure 4 – Installation of Capping on New Southbound Off Slip
Further information
In the coming months, earthworks operations will continue to bring the ground up to the required level. Installation of drainage will also be ongoing.
It is expected that the traffic configuration of the existing northbound on-slip and southbound off-slip roads will remain in place for the next few months. This is necessary for the protection of the public and road users as well as that of the site operatives.
At the start of September, it is expected that narrow lanes will be introduced onto the A46 to create safe working room for the various changes to drainage, earthworks, ducting and lighting on the A46. These narrow lanes will also allow the completion of the work to the new slip roads with an aim to switch traffic onto the new slips and to close the existing slip roads.
Around mid-September, the construction of the new Westley Bridge will commence with the installation of temporary works alongside Finham Brook to allow for the driving of piles to form the bridge’s foundations.