For the isolation test pups were selected randomly from their litter, weighed and placed in a soundproofed custom made plastic box (diameter 13.5 cm). An ultrasound microphone (UltraSoundGate CM16) fixed in the lid of the box 12 cm above the bottom was connected to a preamplifier (...
The excavation diameter is 5.5 m, the ground elevation along the line is 775–1005 m, the topography is not undulating, the relative height difference is 5–35 m and the overburden thickness is 80–295 m. The geological structure of the SS tunnel mainly consists of Tuffaceous sandstone and...