Tunnelling project the Kolle-Kinds Tunnel of Bohusbanan

The first TunnelLing project for the contractor Bohus Bergsprängning AB

Published 2011-05-18 23:27:26

2009 Vägverket, announced the phase “E6, Skee-Ejgst” Rail Road project the Kolle-Kinds Tunnel. 

PEAB Sverige AB was awarded the project, a company which Bohus Bergsprängning AB has a long history of cooperation with, gave the confidence to Bohus Bergsprängning to undertake all rock-work excavation, including enforcement of Koll Kind Tunnel. 

Tunnel Facts:
Single-track railway tunnel without service or escape tunnels, located in northern part of the Bohus rail line.
The length of Tunnel was originally 525 meter, during the construction period shortened to 499 meter.
Height of tunnel 9.25 meter excluding drainage trench 0.5 meter and width 8.30 to 8.70 meter with a Tunnel Area: 73.5 to 76.8 m2 (theoretical section) and Rock Volume of about 45 000m3

Bohus Bergsprängning AB has 20 years’ experience  as an active above-ground blasting company, the owner and founder of the company, felt it was time to expand an also cover the underground blasting segment. A Tunneling group was formed within the company. The primary goal was to carry out a successful tunneling project, which would function as a reference object for the future. 

At that time the company was awarded the railway tunnel at Bohusbanan, near Strömstad. First step was a course how to run tunneling projects, arranged by Michael Hermansson from Bergutbildarna . Thereafter all the networks of the company, was used in order to learn as much possible knowhow, regarding the Tunneling industry.

The start-up was in the end of summer 2010. Bohus Bergsprängning decided at an early stage to ask for help with packing / grouting, rock bolting and concrete spraying. BESAB, with a long experience in these disciplines, became their partner there. The rig was a further a key element which had to be assures access of. The solution was to hire a three boomers rig from Atlas Copco. 

The early and very severe winter and our revised excavation plans meant that we only with great difficulty managed to maintain the schedule of 15 meters per week until the end of the year, when the climate reverted to more "normal" winter conditions, and we managed to increase the speed of 22-28 meters excavation per week. The impact was therefore made on 2011-03-28, seven weeks ahead of schedule.

CME deliver many other kinds of equipment to Bohus Bergsprängning and for the ventilation system they recommended the Swedish fan supplier EOL Ventsystem AB and ducting supplier JP-Jensen Ventilation AB.

EOL Ventsystem AB delivered the complete Fan system. The flexible Duct system was delivered from JP-Jensen Ventilation, which is a close cooperative partner to EOL Ventsystem. They have together, in order to supply a complete Ventilation system, offered and delivered their products to this project.

Bohus Bergsprängning declared they have been very satisfied with the ventilation equipment and the service and support they received from EOL Ventsystem AB and JP-Jensen Ventilation AB.

One of the reasons to choose EOL Ventsystem fans, was due to their separable Modular-Frame-System. The Modular-Frame-System is formed so that each silencer and fan chassis has its own frame. This flexible system allows adding or removing silencers or fans easily, as ex. for a serial fan connection, or disconnection of a multi stage fan. For this project the fans had a bit over capacity, but for the next project it can be the contrary. Since they ordered two identical fans they can easily connect the two single fans, to a serial connected 2-staged Fan.  In that case they will have two spare silencers “left over”, which they can connect to the 2-staged Fan, with the result of extremely good silencing. Also consider that the workers at the site, declared that EOL Ventsystem fans, already was the most silent fans they had experienced.