Long-term monitoring of screw injection anchor in ground

摘要

A screw injection anchor is inserted into the ground at an angle. Before hardening grout is injected, four strain gauges are placed at intervals inside the rod with their connector wires brought out of the proximal end and connected to a resistance bridge. A pressure box rests on the seating. Pressure is applied to e.g. 120 per cent proof by the bolt and a strain gauge measurement is taken. Following removal of the pressure box, the bolt is re-tightened to the appropriate pressure using the strain gauge as reference.