Tunnel Design & Specialities

1km rail tunnel named after the nearby village of White Ball built by Brunel (opened 1844 on the Great Western Main Line). Victorian brick-arch lining, which has deteriorated over the years including weathering and chemical reaction from the sulphurous steam trains. A refurbishment scheme was required to make it fit for purpose which was planned through various phases. The early phases of the project involved installation of the RAM Arch System and wire mesh to prevent loose bricks from falling on to the tracks. In latter phases of the refurb - the subject of the CAT3 check - sprayed concrete applied to cover the RAM Arch system coupled with rock bolts with butterfly plates were used to hold the concrete lining.

The Thames Tideway Tunnel is an under-construction 25km tunnel running mostly under the tidal section of the River Thames through central London. It will provide capture, storage and conveyance of almost all combined raw sewage and rainwater that currently overflow into the river. Once constructed, the main tunnel will have an internal diameter of 7.2m and will run from -30m at Acton, West London for over 25km under central London down to -70m at Abbey Mills in the East. It will connect 34 of the most polluting combined sewer overflows (CSOs), via transfer tunnels. The tunnel will transfer the captured sewage to the Stratford to East Ham part for onward delivery to Beckton Sewage Treatment Works.

The East Side Access (ESA) project provides new Long Island Rail Road services to the east side of Manhattan, supplementing the existing service to Penn Station on Manhattan's west side and Atlantic Terminal in Brooklyn. ESA will serve approximately 162,000 customers a day, providing a faster and easier commute to the east side of Manhattan in a new 8-track terminal and concourse below Grand Central Terminal. The project encompasses more than 13 km of tunnelling.

The East Side Access (ESA) project provides new Long Island Rail Road service to the east side of Manhattan, supplementing existing service to Penn Station on Manhattan's west side and Atlantic Terminal in Brooklyn. ESA will serve approximately 162,000 customers a day, providing a faster and easier commute to the east side of Manhattan in a new 8-track terminal and concourse below Grand Central Terminal. The project encompasses more than 13 km of tunnelling.

The Relief Line South was a proposed expansion to the TTC Line 1 subway with five new stations planned from Osgoode to Pape Station undertaken by the TTC. The project has since been passed on to a new owner (Metrolinx) and further developed as the Ontario Line. Our role on the assignment included the 15% and 30% design for tunnel geometries, excavation and temporary support of two stations and one crossover. Tasks included production of 3D models, drawings, design reports and finite element analysis based on the SEM approach to tunnelling large caverns keeping surface disruption in urban areas to a minimum.

The TTP are delivering a new two track rail tunnel of approximately 176m length crossing the Highway 401. The purpose of the tracks is to increase capacity along the Kitchener GO commuter rail corridor as well as to accommodate the new Union-Pearson (UO) Express service. The new rail tunnels are mined under the 401/409 Highway using the Sequential Excavation Method (SEM). Our role on this assignment was to provide tunnel design services addressing the challenging conditions (e.g., very low overburden, intercepting piles and maximum settlement allowance) as well as providing on site design representation.

North Yorkshire holds one of the largest, high grade polyhalite reserves worldwide. It is located within the North York Moors National Park, ca. 1800m below surface. Once processed, this mineral functions as an organic fertilizer to boost harvest. Sirius Minerals plc are currently developing the infrastructure to mine the polyhalite. This operation requires deep shafts to access the mineral body but also demands an extensive mass transport system (MTS) to keep the impact on the National Park to a minimum. Therefore, at ca. 350m below surface, a series of SCL tunnels link the deep shafts to a conveyor belt system, which again connects the mining operation via a 37km TBM tunnel to its material handling facility.