L'STRALAU TREPTOW-TUNNEL SOUS LA RIVIÈRE SPREE. Le premier tunnel sous-marin jamais construit en Allemagne s'étend sous la rivière Spree entre Stra lau et Treptow et a été en activité depuis son ouverture officielle en 1899. Bien que le tunnel est mais 453 mètres (493,77 mètres) de long sa construction s'est pas une tâche simple pour les sables mouvants dont le sol sous la Spree se compose en grande partie a été déplacé avec quelques difficultés. Le travail préliminaire a été commencé à l'été 1895. Mais la tâche de retirer le sol dans la ligne du tunnel n'a pas commencé jusqu'à la fin de février 1896
Cette image peut avoir des imperfections car il s’agit d’une image historique ou de reportage.
THE STRALAU-TREPTOW TUNNEL UNDER THE RIVER SPREE. The first submarine tunnel ever constructed in Ger many extends beneath the River Spree between Stra lau and Treptow and has been in active use since its formal opening in 1899. Although the tunnel is but 453 meters (493.77 yards) long its construction was no simple task for the quicksand of which the soil beneath the Spree is largely composed was re moved with some difficulty. The preliminary work was begun in the summer of 1895. But the actual work of removing the soil in the line of the tunnel was not commenced until the end of February 1896 because the tunneling-shield was delivered too late. Despite this delay 160 meters (524.8 feet) of soil had been excavated by the end of autumn of that year. A second in terruption of the work was caused by the deliberations of the authorities as to whether the street railway should be extended so as to pass through the tunnel under the river. Finally work was again resumed in September 1897; and in February 1899 the last shovel ful of soil was removed and the last rivet driven. The tunnel crosses the line of the river approximately at right angles the width of the stream at that point being 195 meters (212.55 yards). So deep is the tunnel that between its roof and the river-bed there is still a layer of sand some 3 meters (9.8 feet) in thickness. The lowest point of the tunnel lies 12 meters (39.36 feet) be low the mean water level of the Spree. In the direction of Treptow to Stralau the tunnel is built on a downward incli nation (1:20) but becomes more level as it passes under the river (1:600). The tunnel tube is composed of cast iron annular segments varying in which are connected by screw-bolts. Between the rings or annular segments flat iron straps are laid which appear externally as corrugations and serve as reinforcing and stiffening members. Externally the tube is covered with an 8-centimeter (3.2-inch) layer of cement and internally with a 12-centimeter (48 inch) lay
