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Tunnel support in South African mines
Published in Xia-Ting Feng, Rock Mechanics and Engineering, 2017
– Example 1: Straps and anchors – applied where tunnel deformation is likely, often installed over existing meshing and lacing. A regular pattern of 4.5 m or even 6.5 m long cable anchors are installed around the perimeter of the tunnel spaced approximately 1.5 m apart in a block pattern. The anchor cables are threaded through multi-strand narrow straps (Osro / Oslo straps) which are installed over the anchor pattern prior to the anchors being tensioned, thus locking the straps under the anchors’ load-spreading washers. The straps provide a load-spreading function between the different cable anchors.– Example 2: Steel arches or ring sets, combined with void filling – used in extreme cases, such as where the ground conditions do not allow reinforcement of the rockwalls using tendons or cable anchors, or where deformation of the tunnel cannot be contained by other methods. The arches or ring sets are passive support, so the void between the support and the adjacent rockwalls must be filled to provide some form of support and impact resistance. An example of steel arches being used to support the entrance of a chairlift excavation from surface is shown in Figures 12 and 13.
Tunnel support in South African mines
Published in Xia-Ting Feng, Rock Mechanics and Engineering, 2017
– Example 2: Steel arches or ring sets, combined with void filling – used in extreme cases, such as where the ground conditions do not allow reinforcement of the rockwalls using tendons or cable anchors, or where deformation of the tunnel cannot be contained by other methods. The arches or ring sets are passive support, so the void between the support and the adjacent rockwalls must be filled to provide some form of support and impact resistance. An example of steel arches being used to support the entrance of a chairlift excavation from surface is shown in Figures 12 and 13.
Thermoregulation and shivering responses in elite alpine skiers
Published in European Journal of Sport Science, 2021
Marine Alhammoud, Juha Oksa, Baptiste Morel, Clint Hansen, David Chastan, Sebastien Racinais
The relative muscle activity of the HAM (P = .031), but not QUAD (P = .116), was also lower during the last lift than the first one (Figure 4). Conversely, the MDF and MPF of both QUAD and HAM were higher during the last lift than the first one (all P < .019, Figure 4). Visual inspection of the first-last chairlift wavelet transforms spectrogram maps revealed that the signal power below 50 Hz markedly decreased by 20–40% between last vs. first chairlift, for both QUAD and HAM (Figure 4). Conversely, the power above 50 Hz did not display major changes for QUAD and showed a slight decrease for HAM (0–20%).