The device null which gives the preload for the floor where the bottom of the foot of the arch which is used for tunnel excavation is easy

摘要

The proposed system for preloading the support surface of the feet of supports for galleries is realized by way of a foot supports with a special use made up of a rigid upper plate, and a lower counterplate in pliable steel welded to the upper one. Between the plates there is a space that is inflatable through the injection of a suitable pressurized cement mixture. The injection causes the deformation of the lower plate that is consequently pushed down causing a reaction on the surface of the bottom. The upper plate of the support has an input valve for the mixture with a gate valve as well as a vent with a closure plug.IMAGE