@inproceedings{oai:kutarr.kochi-tech.ac.jp:00001067,
 author = {Haack, Alfred},
 book = {Society for Social Management Systems Internet Journal},
 issue = {1},
 month = {Mar},
 note = {Since 2004, the 3.8 km long North-South-Metro Line in Cologne with 7 underground stations is under construction. The running tunnels were excavated by Tunnel Boring Machines (TBM) and finished already in summer 2008. The stations, two emergency shafts, and an underground turn-off are to be constructed by special methodologies, applying partly cut-and-cover methods, partly mining methods in combination with ground freezing. On March 3^<rd>, 2009 in the open pit of the 28 m deep turn-off, an inrush of groundwater and ground material occurred and resulted in a total collapse of the Historical Archive of the City of Cologne consisting of five storeys above ground and two storeys underground. The archive contained about 33 km total length of shelves with historical documents partly going back to the 9^<th> century, covering not only the history of the City of Cologne but also of the entire surrounding region and all Germany. Collaterally, one neighbouring building on each side of the archive also collapsed. Two fatalities were missing for a couple of days, covered by masses of meter-high debris. So far neither the technical nor the first juridical investigations are finalized and the earliest results are not expected before the end of spring 2010. Therefore, all explanations regarding the reason of the accident are based on assumptions only. A possible explanation seems to be a failure in the diaphragm-walls of the shaft, not visible from the bottom of the shaft, for example a larger hole or a severe honeycomb or a weak joint between two neighboured wall sections. A hydraulic ground seepage could also be the reason for the accident. This will be clarified by special investigations like seismic impulses or by digging out the deeper parts of the diaphragm-wall. The paper describes the construction methods applied, the first political reactions after the accident occurred and the consequences taken after the accident},
 publisher = {Society for Social Management Systems},
 title = {Construction of the North-South-Metro Line in Cologne and the Accident on March 3rd, 2009},
 volume = {6},
 year = {2010}
}