Why tunnel CD method in the middle of the steel support to be bent
Set the outer radian to resist lateral pressure to achieve a more stable structure.
Because the CD method of construction generally from the upper left corner of the excavation, to ensure that the supporting force evenly
Especially in the middle of the steel support for the removal of the time should be in the whole section into the ring, the displacement of the parts are fully stable, in order to dismantle.
