i've always wondered why they don't just like slip form concrete behind the cutting faces to make a concrete shell lining tho i imagine its probably due to the curing time, but then couldn't you just make the slip form / tunnel shield longer so that but the time the concrete reaches the end of the slip form its cured enough to take the weight ?
Concrete curing isnt the problem, concrete itself is. With no yield point or elastic limit, its ultimate limit is the failure point. Hence, other than injecting concrete and waiting for it to cure, you would need to think about adding in steel casings for reinforcement. Then we are talking about the same timeframe as building constructions. To be able of achieveing 26m of tunnelling/day and ending up completing the project one year ahead of schedule they are doing much more than just 26m/d. Hence when time is an issue alternatives are considered.
Good, but it does not explain the cutting blade and the operator's work
i've always wondered why they don't just like slip form concrete behind the cutting faces to make a concrete shell lining tho i imagine its probably due to the curing time, but then couldn't you just make the slip form / tunnel shield longer so that but the time the concrete reaches the end of the slip form its cured enough to take the weight ?
Concrete curing isnt the problem, concrete itself is. With no yield point or elastic limit, its ultimate limit is the failure point. Hence, other than injecting concrete and waiting for it to cure, you would need to think about adding in steel casings for reinforcement. Then we are talking about the same timeframe as building constructions. To be able of achieveing 26m of tunnelling/day and ending up completing the project one year ahead of schedule they are doing much more than just 26m/d. Hence when time is an issue alternatives are considered.
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