Installing vertical drains

摘要

A mandrel shoe 1 for the installation of vertical drains has a guide channel 10 extending from an upper end 11 of the mandrel shoe to a side opening 12 formed in a lower end of the mandrel shoe. The guide channel is adapted to direct a length of drain from an upper end of the mandrel shoe towards and out of the side opening. In this way, an anchoring length of drain projects from the side opening to anchor the drain within the ground. The shoe includes a cutter 18 which cuts the drain when the mandrel and shoe are raised above the ground causing a stop 30 on the rig to depress a plunger 15. Movement of the plunger in the opposite direction when the shoe starts to move towards the ground operates a feed roller 20 to feed a length of drain from the side opening 12 to form the anchor section for the next drain.