Toronto, Ontario
1996
ECO designed as a sub-consultant to D.S. Lea Consulting Engineers, the grouting program to install a new sewer tunnel (3.6 meter diameter) below the existing subway. ECO designed and directed the compensation grouting program.
The actual compensation grouting program was conducted from two shafts. Two fans of steel sleeve pipes were installed. The tunneling contractor used a rib and lagging system behind the EPB shield. The length of the crossing was approximately 35 meters. Horizontal monitoring pipes containing inclinometers connecting to a central monitoring system were installed above the grout pipes. Three grout formulations containing various proportions of fly-ash, bentonite and cement were developed for the compensation grouting.