#difficultaccess

[geotechnicsblog-blog]

[Photo] Our specialist modular rig enables us to access hard-to-reach parts of the rail network 

Rail Geotechnics Site Investigation Case Study: NWEP

The North West Electrification Project (NWEP) is working towards the electrification of over 300km of the rail network, improving key routes between towns and cities including Manchester, Liverpool, Preston and Blackpool. From April 2016, Geotechnics carried out works to inform design of gantry installations for the proposed overhead line equipment on Phases 4 and 5.

We worked on track during weekend and midweek possessions, and our site investigations have primarily focused on collecting geotechnical and environmental information for the project. Another significant section of work has been aimed at locating and identifying shallow mine workings in the area.

The rail network presents a unique set of challenges, not least in gaining access to borehole locations with drilling rigs and significant amounts of equipment in this safety-critical environment. Geotechnics’ Project Manager Steven Chapman built up a strong working relationship with the client in order to overcome any issues. Our collaborative approach – including early engagement with the client, liaison with stakeholders, regular progress reporting and change control – has been critical to our success on the project.

One solution for accessing borehole locations was Geotechnics’ specialist modular dynamic sampling rig. This rig can be broken down into its constituent parts, which enables it to be moved more quickly and easily into hard-to-reach areas than conventional equipment allows. We have also used Road Rail Vehicles (RRVs) to lift rigs and equipment into positions in the cess, 4 foot and onto station platforms.

Off-track works have also been completed for proposed distribution compounds, as well as an investigation for a proposed section of horizontal directional drilling to install 25kv electrical cabling. This section of the works included deep rotary boreholes, in-situ packer permeability testing and specialist rock testing.

On completion of significant geotechnical, rock, concrete and environmental laboratory testing, Geotechnics produced factual and interpretive reports on time and on budget. These reports include data sheets for each gantry location, detailing the ground conditions, foundation solutions, groundwater conditions and environmental considerations.