SCL and rock tunnelling

Photo: COWI
When cross-sections of varying dimensions or short tunnels are required, shotcrete-lined tunnels constructed as either rock tunnels or NATM tunnels are often a feasible solution

Choice of construction method
The selection of construction method is based on ground and water conditions and environmental requirements. Additionally, it is based on risk assessments of the proposed methods.

Risk and safety
Tunnelling with sequential excavations carries risks. As part of these projects COWI always performs a risk analysis which identifies hazards and consequences to reduce risks and improve safety.

Ground conditions
COWI's experience of sprayed, concrete-lined (SCL) tunnels has been gained mainly from the design of underground infrastructure with ground conditions ranging from clay and sand pockets to limestone and highly weathered rock.

COWI’s experience encompasses primary linings of shotcrete and permanent linings of either in-situ cast concrete or sprayed concrete with a waterproofing membrane.

During construction work our design and geotechnical engineers cooperate closely to ensure that the tunnel lining is carefully monitored for convergence with actual ground conditions.

LAST UPDATED: 07.02.2017