Orange County Sanitation District
Ellis Avenue Tunnel

Guida provided surveying services for this 1.3-mile tunnel with several tight bends with radius of only 500 feet, using a Herrenknecht EPB 2400TB tunnel boring machine. The tunnel was constructed of rib and lagging. This project included providing control at the bottom of the pit, control for the driving the Herrenknecht gyro system using the UNS system. The project also required the use of high accuracy total station and gyro total station for survey control.