Southam News

Details have been released pertaining to tunnel design for the proposed rail link and, specifically, to the Long Itchington tunnel.

From HS2 Ltd:

"This note gives a brief description of the HS2 tunnels and the expected levels of noise and vibration. The design of HS2 is still at an early stage, and we are continuing to work on it, so that during public consultation we will be able to demonstrate how the four main tunnels would be built and operated with minimal noise and vibration.

The tunnels would be built through a variety of soil conditions, including London clay and chalk. However the key determinant of any noise and vibration is the design of the track and associated components – known as the trackform.

Trackform (rails, sleepers, supporting substructure and rail fastenings)
The track design for tunnels in the vicinity of properties and other sensitive locations, such as schools, hospitals and meeting halls, would use the latest modern trackforms. We would design all four tunnels to meet stringent engineering and environmental criteria in order to minimise track borne noise and vibration in all types of ground conditions.

We will examine systems recently used on other high speed systems, particularly HS1 whose systems were developed for similar ground and urban conditions. The systems adopted by HS1, Crossrail and other international rail projects including Cheonan Station (Korea), Germany, Japan and France have trackforms specified and designed to isolate the vibration from train wheels. These projects include tunnels under locations such as the Barbican Concert Hall, high density urban and other sensitive properties.

Long Itchington Wood Tunnel
This short tunnel (1.4km) would be a single bore with an internal diameter of 12.8m. The diameter would be necessary to alleviate the aerodynamic effects from the speed planned for this part of the route.

Ground conditions and underlying rock strata in the vicinity of this tunnel are known to be mixed; so until a full geotechnical investigation has been carried out, we would not determine whether the tunnel would be constructed using a road header drill with spayed concrete lining, or a tunnel boring machine".

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