Drain construction system - comprises freezing ground before excavating and lining shafts with permeable material before thawing

摘要

The drain construction system, for use especially in water-bearing ground where excavation is made difficult, consists of consolidating the ground by freezing it in the are the area in which the drain is to be located, digging out the vertical and horizontal drain shafts (5,9) and lining them with a material which is permeable to water before allowing the ground to thaw out. - The horizontal shaft can be angled so that the water seeping into it can run down into a sump at the bottom of the vertical shaft, from which it can be pumped out.