FRANKFURT, Germany — Following the collapse of a new high speed rail tunnel being built underneath the German town of Rastatt, about 100 miles south of Frankfurt am Main, the existing main line railway directly above the damaged tunnel workings...
http://trn.trains.com/news/news-wire/2017/08/23-tunnel-collapse-closes-key-european-international-route-for-2-weeks-or-more
Brian Schmidt, Editor, Classic Trains magazine
Now they can't get it re-opened even with temporary line until October seventh??? Even with grouting the TBM in its hole, or even putting coils under the sinkhole area and freezing it solid temporarily?
Heck, if it's that important, why not do an emergency excavation, put in a temporary bridge, and handle the new-line construction as if in a cut with uncertain subgrade when the time comes for the trackwork? We've seen how quickly bridges can be replaced or erected when need be...
Note to Volker Landwehr: will you please post here all the links to the German-language reports and remediation discussions that are in the other thread? It should help any ongoing discussion of this new development.
(As an 'aside' for discussion, this is very similar to the proposed scenario where the ex-PRR North River Tunnels are catastrophically closed. I wonder if there are valuable 'lessons to be learned' out of the German experience that will be valuable if that were to happen.)
RMEHeck, if it's that important, why not do an emergency excavation, put in a temporary bridge, and handle the new-line construction as if in a cut with uncertain subgrade when the time comes for the trackwork? We've seen how quickly bridges can be replaced or erected when need be...
First some information about the TBM: It is about 310' long and weighs about 2,000 tons. The assembly on site took about 12,000 hours. Here is an interesting video though it is in German: https://www.youtube.com/watch?v=TqSiOG7LHXA
Your guess is as good as mine how long it would take to disassamble the TBM.
The bridge you mention needs a span of about 400 ft and don't forget the needed heavy foundations. See aerial view: https://abload.de/img/zwischenablage03eksn3.jpg
The freezing alone would take approximately six (6) week not taking into account the time for installation.
I don#t think all this would be faster than what is planned now: A concrete slab 400' long, 50 ft wide and 3'-4'' thick.
Both contractors, Zueblin and HOCHTIEF, are very experienced. Here is a link to a description of HOCHTIEF: https://en.wikipedia.org/wiki/Hochtief
The Wiki-article is a bit old but still a quite good overview. I've worked for HOCHTIEF in structural engineering for more than 30 years. I'm sure they know why they go for this solution and without knowing all boundary conditions and requirements I'm not in a position to judge that decision.Regards, Volker
P.S.: Is there a way to link single post in this thread? http://cs.trains.com/trn/f/111/p/264617/2989834.aspx#2989834"Rail Traffic Chaos in Southern Germany"
Otherwise it would be nice if the moderaters would merge the threads.
I'll try to merge some information here.
Subsoil: The tunnel is bored in medium densely to densely bedded sand and gravel from the Tertiary and Quaternary. The layers near to the surface are sandy clay and silt.
Tunnel coverage: The tunnel roof is about 60 ft beneath the surface. The two exceptions are at the ends were the tunnel comes back to the surface. The minimum coverage of the TBM tunneling is approximately 15 ft. One of these locations is the crossing of the existing rail line.
To go through with a TBM the soil gets frozen around the tunnel section to between -1°F and -27°F made possible by a high ground water level.
Included on the site is exploded view with detail explanations: https://www.herrenknecht.com/uploads/pics/130228_TPG_Schnittgrafik_Mixshild_S-623_960_01.1365178380.jpg
There are 56 m (183') left to the end shaft. "Schaden" means damage. The additions are based on the offical DB progress report.
Owners design: On the other side of the rail line is another shaft. That was the original end of the TBM tunneling. Between the two shafts a different method using sprayed concrete within frozen soil was suggestion by the owner. That was changed by the contractor with the agreement of the owner to TBM tunneling to the second shaft.
At the first glance sprayed concrete against frozen soil seems to be impossible but on the other hand there are lots of tunnels all over Europe that have been built that way. Fahrlachtunnel Mannheim, Germany: http://www.daub-ita.de/fileadmin/images/daub/TunnelDB/UBD1995134-02.jpg
Frostkoerper = Frozen soil; Spritzbetonschale = Sprayer concrete shell; Bauzustand: Intermediate state; Endzustand: Final state;
A Portland cement is chosen as it delivers the highest hydration heat of all cement types. Additionally an accelerator is added.
Here is a link to a German tunnel project in Berlin written in English: dc.engconfintl.org/cgi/viewcontent.cgi?article=1008&context=shotcreteRegards, Volker
Here are a few more informations of today:
A DB board member was quoted in newspapers saying: Water ingressed a short distance behind the TBM's shield. Two days later one tubbing segment was displaced by about 20'. That segment was placed one week before the accident.
The ice shield and the seals within the structure should have prevented this.
Tunnel tube backfill: According to different press releases of Deutsche Bahn and media reports tubbing segments were displaced on a length of approximately 130 ft behind the TBM's shield with ingress of soil and water. Sounds like a kind of zipper effect.
The tunnel will be filled with concrete on a length of about 500 ft a total of about 130,000 cubic feet of concrete burying the TBM.
Here are two drawing illustration the intentions:https://inside.bahn.de/wordpress/uploads/2017/08/Tunnel-Rastatt_Rheintalbahn_Sperrung_Reparatur.jpg
Here are some translations:Verfüllung der Tunnelröhre: backfill of tunnel tube Bohrungen: bore holes Verbruch: caving Schadensbereich: damaged area Verfüllung: backfill Schild: TBM shield
If the true cause will be found is doubtful, as the damaged area gets buried.
How to restore and finish the tunnel is not detemined yet though a board member of Zueblin suggested that there are ways to open up the tube in spite of the TBM.Regards, Volker
Endzustand: final stage Wiederherstellung des Oberbaus und der Gleise: rebuilding of roadbed and track
North River Tunnels? where? on the Susquehanna RR Brdige north of Harrisburg?
The North River is the 'official' name of the river to the west of Manhattan Island, just as the East River is the official name of the river to the east.
It actually makes sense! because the Hudson was the highway 'north' to Albany and the Canal.
The North River tunnels are the ex-PRR tunnels under the Hudson, crumbling after 100+ years and Sandy immersion.
Can I presume the tubing segment displaced by 20 feet, was displaced in the vertical direction?
MidlandMikeCan I presume the tubing segment displaced by 20 feet, was displaced in the vertical direction?
I'm very sorry, it should have read 20 inch.
A direction was not given but I assume it might have been in radial direction.Regards, Volker
RME The North River is the 'official' name of the river to the west of Manhattan Island, just as the East River is the official name of the river to the east. It actually makes sense! because the Hudson was the highway 'north' to Albany and the Canal. The North River tunnels are the ex-PRR tunnels under the Hudson, crumbling after 100+ years and Sandy immersion.
It's been an alternate name for years and was originally used by the Dutch.
North River Wiki article
C&NW, CA&E, MILW, CGW and IC fan
https://archive.org/stream/sloopsofhudsonhi00verp#page/n25/mode/2up
https://archive.org/stream/oldbergenhistory00vanw#page/n11/mode/2up
https://archive.org/stream/newyorkpanoramac00federich#page/22/mode/2up
Vee almost had zee whole vorld, vee vere ziss close!
I am still trying to understand the 20" offset in the tubing. Did two liner ring segments seperate, and thus there was a parting of the tube?
The warmth of the rainwater may have contributed to a reduction in the diameter of the "Ice Ring".
MidlandMikeI am still trying to understand the 20" offset in the tubing. Did two liner ring segments seperate, and thus there was a parting of the tube?
I found just this statement no further details. If you look at tubbing segments the can't be pushed out easily as their outer arc length is longer than an inner opening: http://www.rastatt.de/fileadmin/Stadt_Rastatt/Bilder/Inhaltsbilder/Rathaus_u_Politik/Presse/2017_Pressemitteilungen/2017_5/265-2017__T%C3%BCbbinge.JPG
That only works if a joint gets pushed in. On the other hand there is the key-segment: https://1.f.ix.de/scale/geometry/700/q75/tr/imgs/08/7/6/7/1/4/6/Online_Tunnelgeothermie_Tu__776_bbing_1826.jpg-b738c7d16e727f9a.jpeg
It is seen here at the tunnel top. To put it in as last segment outer length and inner opening have to be of equal length. It could be pushed in as single segment. It is not always at the tunnel top as the following drawing shows: http://www.vde8.de/mediathek/file/2036/dToFyLnkH0Bu24dvcJU-Usm1JTlViZHj_qXh0g8Yh7s/finne_tuebbinge2.jpg
As the displaced segment moved one week after being set it was only able to move inwards. To the left and right were other liner rings. Yes, a longitudinal joints must have been forced open. The crack must have spread like a zipper effect over about 130'.
Here is a photo inside the tunnel Rastatt: https://www.bo.de/sites/default/files/styles/artikeldetail/public/field/image/reiffit_ortenauticker_5615230e06b67.jpg?itok=onh8xmbJ
It shows that the conical and smaller segments are staggered against each other. That make a zipper effect even less understandable.Regards, Volker
Edit: Perhaps we have to take the 20'', given in a press conference, with a grain of salt. A newspaper report from a meeting of DB personell and town inhabitants talks of 4'' displacement.
A DB fakt sheet states: 40 meters (130'), on this length water and earth entered the tunnel on August 12th 2017, after tubbing segments were displaced.
Looking at the tunnel inside I'm not sure anymore. How could there be zipper effect and a 130' liner damage with the staggered segments?
Or did they mean there was a 130' long damage on the surface and in the soil?
Here is a built tunnel that might have been used as guide and perhaps led to too optimistic conclusions.
Fahrlachtunnel Mannheim: http://www.daub-ita.de/en/tunnel-projects/deutschland/fahrlachtunnel-mannheim/
Here we have an ice ring with a tunnel built with miner's method as specific proposal. Ironically the owners proposal was using a TBM. The tunnel crosses a railyard and mainlines carrying freight and passenger traffic.
Differences: Soil coverage minimum 23' instead of 13', much less rail traffic, no pedestrian underpass cutting into the ice ring, no special frost-proof grout needed.
I haven't found anything about the influence of vibrations on the freezing process, not temperatures but on tensile strength. Perhaps someones knows something?Regards, Volker
I thought the tunnel ring segments were formed and cemented in place, but I see that instead they were pre-formed and assembeled into place.
"The ingress of water and earth spread to a length of approximately 130 feet." I thought this meant that the water and sand came in thru a small hole (offset?), and then spread a distance down the tunnel.
MidlandMike I thought this meant that the water and sand came in thru a small hole (offset?), and then spread a distance down the tunnel.
You could be right. As an civil engineer I didn't grasp this interpretation as these 130' would only have to be cleaned not repaired. I hope some day will get the details. But DB is not bound to make the accident report public. Hopefully the outside pressure is high enough to do it.
The second TBM in the West Tube resumed work. To prevent a similar desaster a second concrete slab is built to protect the crossing of West Tube and mainline.
Re-opening of the mainline is still scheduled for Oct. 7th 2017Regards, Volker
The North-South mainline through Rastatt (Rheintalbahn) was reopened tonight after 51 days.
There is no new information what might have caused the tunnel collapse.
How did they finally decide to proceed? More ground freezing? Entombing the TDM in concrete as stated? Be interesting to see how the professionals did things...
Link is an editorial about the need to plan for disruptions of a main line in the EU . There are many lessons listed that need to be considered for the USA as well. Comments ?
http://www.railjournal.com/index.php/blogs/tony-berkeley/rastatt-was-a-disaster-for-rail-freight-lets-learn-the-lessons.html?channel=
The article is a somewhat self serving document for the freight shippers who want to displace passengers and be compensated during route interuptions.
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