Sireg Geotech’s Durvinil® SD system is formed by a self-drilling steel head that drags a PVC Durvinil® drainage slotted pipe, used to reduce the soil’s water pressure.
This system is used to install the drainage pipes in loose soil or below the groundwater table, where it is not possible to apply the provisory coating in the drilled holes before the insertion of the pipe. It can also be used to insert the pipes through the TBM’s shield, in order to drain the soil before excavation as the TBM moves forward. The presence of PVC Durvinil® in the soil doesn’t hinder the grinding by an excavation bucket or by the TBM itself, which would be impossible if steel drainage pipes were used.
The Durvinil® SD system includes:
– a disposable metallic self-drilling crown with a threaded border where the drainage pipe is fitted;
– a reusable pilot tip that attaches to the crown during drilling and is recovered after the drainage pipe is installed;
– steel drilling rods;
– a PVC Durvinil® slotted pipe with 75 mm external diameter which, thanks to the pilot tip and crown, does not endure rotation during drilling.
The density and depth of the drainage pipes implanted vary based on the project, the soil’s characteristics and the specific drilling probe available.