Navigation control is one of the most critical elements for successful microtunneling. Design criteria installation accuracy is maintained using active laser guidance systems.
A shaft station reference laser is positioned on line and grade behind the jacking frame and protected from disturbance. The laser is projected down the tunnel onto the MTBM’s active target at the design’s line and grade. The MTBM contains three inclinometers read and transmit the MTBMs pitch, yaw, and incline data coordinates. Target sensors relay this data to where it is numerically displayed on the operator’s control console.
- Light sensitive TGS100 active target reads the laser beam and transmits x and y coordinates and MTBM incline to the control console interface
- Reads the location of the most intense light
- Two redundant inclinometers to measure MTBM pitch and roll
- Target display screen displays current and projected cutter head position
- System logs over 100 data points for customized reporting to track and graph alignment deviation, face pressure, and torque changes.
Microtunneling Guidance System
I have used TBM equipment since 1996 for the installing pipes from 1.22 m to 2.44 m of internal diameter, they are very efficient in clays and silts with a high content of humidity.
I have also used GBM systems for driving smaller diameters in soils soft from the Valley of Mexico and are suitable for these conditions.