The election of this type of perforation is influenced in great way of the type of ground and surface area of influence. Is absolutely necessary not to have groundwater levels and the ground has to be cohesive. This boring technic is inadvisable in free ground without cohesion, hard ground or in water presence.
The execution of pipe jacking with open shield, is realized by a SHIELD that has incorporated a perforation tool, depending on the ground condition can be used an excavator arm or roadheader.
The extraction of the material is carried out by wagon. The shield is articulated and can be guided by the orientation cylinders place between the first and second shield. And as close face TBM, the machine is guided by a laser beam that marks the orientation and slope of the drive. Eurohinca Website.