The jacks that Payab Zamzam uses are manufactured by OVM Company. YCWA and YCWB series are very common. Both can be used for post/Pre tensioning operations. They can also be used for ground anchoring operations. If some peripheral accessories are attached to these, they can be used also for stay cable installations too.
Series YCWA come in 650, 900 and 1200 ton capacity while Series YCWB comes in 100, 150, 250, 400 and 500 tones. The weight of YCWA series varies from 960-1700 kg but YCWB jacks are lighter (65-533 kg).
Some of the applications of this instrument are:
- Measurement of deformation around tunnels.
- Monitoring rock displacement in metro stations.
- Stability assessment in shafts and mine tunnels.
- Measuring mine roof movement.
Operation and Installation
Several pins are installed around periphery of tunnel by drilling and grouting. The convergence meter is attached from its both ends to the pins and a spring loaded handle pulls the tape to remove the slack. Once the force on tape reaches a preset value, the system locks. Meters and centimeters are read from the tape and millimeters and 1/100 mm is read from the gauge. The same thing repeats in coming days or weeks and rock displacement versus time is plotted. The amount of displacement as well the rate of displacement is used as a guide to judge about the stability of tunnel
- X: Dial Gauge (B) or Digital Gauge (C
- AA: Tape length (15 or 30m