Tunneling in any environment can be tricky. Add North coast weather and a remote or tunneling projects site now and now it gets really interesting.
Constructability in Tunneling
On any tunneling project there are many different long lead items that must be addressed. As Arrowsmith is not a designer we are not involved in the design issues of the Tunnel Boring Machine (TBM) or any of the geotechnical concerns.
We do however become involved in the constructability, access and mobilization activities that become critical to any remote projects success.
Questions like how do we get up there? Where is the camp? What are the roads like? These might seem second nature to anyone in an urban centre but in the middle of the remote northern coastal mountain ranges of British Columbia, these do not always have simple answers.
Arrowsmith will engage with survey crews, geotechnical engineers and civil engineers to develop access planning, site staging and site laydown areas for everything associated with remote activities. This would include pioneer and construction crew camps, waste management systems, potable water and electrical generation and vehicle and heavy equipment fuel supply and storage.
Service Roads in Remote Tunneling
Often these sites already have skidder tracks or other back country trails that can be improved to function as access roads. In the cases where these don’t exist, we go back to the principles of the basic road prism, weight and width of the heaviest vehicle and lastly length.
Weight and width assist in the development of quantities of crushed rock required whilst length critically defines the space needed should something overlength be required to get to a particular location. Then there are discussions of grades, switchbacks and passing zones.
As roads are punched and set to various work fronts, laydown and staging areas are created for the storage of construction equipment, temporary offices, construction camps and servicing sheds. Depending on locations, these areas must be logged, cleared and grubbed with all the overburden removed so that imported subbase materials can be brought in for the preparation of these areas. In cases where these conditions are less than ideal, then geosynthetics are used either practically or on the recommendation of the geotechnical or civil engineer.