Results from the Untersammelsdorf test field for the planning of tunnelling work / Erkenntnisse aus dem Versuchsfeld Untersammelsdorf für die Gestaltung der Vortriebsmaßnahmen

In the western part of the Koralmbahn railway line, tests were carried out as part of planned specialised civil engineering works in silty to sandy still water sediments in order to find out about the interaction of jet grouting and dewatering measures with this ground, which is considered to be as geotechnically relatively unfavourable. Small-scale tunnelling work was also carried out to gain experience for the later tunnel construction work in this area. The most important discoveries were: that the jet grouting trials achieved jet grout columns with a diameter of 1.5 m within the still water sediments; and the simulation of a tunnel drive was able to demonstrate that stable conditions at the face can be achieved with the chosen advance support measures. The evaluated results made it possible to optimise the design of the tunnel structures and the forecast performance rates for the grouting works.