Population in Rogaland and Hordaland is expected to increase from over 900,000 to-day to 1,400,000+ by 2050 and about 3,000,000 by 2100. One way two traffic lanes per tunnel will cause traffic capacity problems in the future and increase the rate of traffic accidents considerably. One TBM tunnel can excavate for 4, 5 & 6 traffic lanes. Mega long tunnels like Ry- & Rogfast must have multiple lanes.
Road tunnels in Norway offer little safety for drivers. Mixed traffic use same traffic lanes. The possibility for an accident between heavy-duty vehicles and passenger cars is always present and usually involves loss of human life. In tunnels over very long distances drivers are subject to higher stress levels and more concentration is needed driving in a confined area.
A straight tunnel construction without niches is a better engineering concept. However if niches are a must a somewhat larger diam. TBM would allow for an emergency lane throughout the whole tunnel. Even though the primary object is to have the highest traffic capacity in the smallest constructed area.
'' Madam Felle '' is history. It is from a time when 50 mtr2 was a large TBM. To-day 100 mtr2 is normal and TBMs are 3 x more powerful than before. Large TBM diam. means more traffic lanes per tunnel.
Large volume multiple probing, like rock bolting, can be done while boring, saving huge sums of funds and time. Further in competent rock use thin high tech liner plates instead of thick segments and use a bigger ID to add more traffic lanes. LCC (Life Cycle Cost) report, a big advantage for choosing TBM, should always be issued.
Present D&B tunnels need a rectangle of 4.60 mtr high and 8+ mtr long to accommodate heavy-duty vehicles. Amounting to only 15 % of total traffic while the other 85 % are passenger cars able to use smaller heights. D&B uses 35+-mtr3 excavation for one meter traffic lane advance for T9.5 D&B class.
Instead of choosing a TBM size to compete with D&B MCS would recommend a modern larger TBM to accommodate 2 decks with together 4 traffic lanes (8 lanes for dual tunnels). The TBM tunnel could be from 88 to 96 mtr2 and average traffic lane would only need 22 to 24 mtr2/traffic lane mtr advance vs. D&B 35 mtr2, a difference of up to 60 % in excavation and important costs & time construction factors. Similar advantage with 5 and 6 traffic lanes, all in one TBM bored tunnel.
Infrastructure for 2 levels can be build while boring.
At Ryfast the difference in excavation could be 1,000,000 mtr3 rock and at Rogfast 2,500,000.
To make this possible we would move trucks & busses to the lower (4.6 mtr) deck and passenger cars to the upper deck. Both area would be smaller than your present D&B sizes used (see picture) because the lower deck would have a flat roof and the upper deck does not need 4.60 mtr height.
In addition by separating this traffic, you increase passenger safety dramatically.
For single traffic tunnels a 4 lane over 2 levels TBM tunnel would allow vertical escape between levels in case of danger, avoiding the need of an additional escape tunnel.
MCS suggests TBM projects like:
1. Ryfast and Rogfast
2. A 25 km single tunnel at Haukeli for all year snow free traffic between Oslo and Bergen.
3 . A parallel 4 traffic lanes TBM tunnel to your present D&B Oslofjordtunnel and use your present tunnel for one-way traffic only.
Pictures:
TBM 88.3 mtr2 compares with 141.78 = 2 x T9.5
TBM 108,4 mtr2 compares with 161.61 = T9.5 + T11.5
Click for larger image.
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