Cut and Cover
Definition - What does Cut and Cover mean?
The cut and cover method is also known as the open cut method. It is a traditional form of tunneling that involves opening up the ground surface and excavating to the required depth. Shallow tunnels are built using this method where a section is excavated and then covered with a support system.
Unlike trenchless construction techniques such as horizontal directional drilling (HDD) and microtunneling, the cut and cover method requires traffic diversion for the duration of the project. The surface of the excavated site is restored to its original condition once the project is complete.
Trenchlesspedia explains Cut and Cover
The cut and cover method can be of two types namely, bottom-up method and top-down method.
In the bottom-up method, the site is first excavated and proper ground support is provided. The tunnel is then constructed of precast concrete, in-situ concrete, steel rings etc. Once the tunnel is completed, the trench is backfilled over the tunnel roof and the ground surface restoration is carried out.
In the top-down method, cap beams and side support walls are constructed starting from the ground surface down with slurry walls or secant piling. The tunnel roof is then made of precast beams or in-situ concrete from a shallow excavation. Leaving opening for access, the ground surface is restored allowing restoration of traffic services. The remaining construction is then carried out under the tunnel roof from the access openings.