EPM achieved the closure of the first gate of the Auxiliary Deviation Gallery of the Ituango hydroelectric project

In an underwater engineering maneuver, today Wednesday, May 29, the closing of one of the two gates of the Auxiliary Deviation Gallery (GAD) was made, in a new milestone in the work of risk mitigation in the Ituango hydroelectric project.

As will be remembered, the contingency in the Ituango hydroelectric project started on April 28, 2018 with the obstruction of the auxiliary diversion tunnel (GAD). In September of that same year, specialized personnel entered the GAD gates chamber and found that the two floodgates, each of 300 tons in weight, had moved 15 meters.

With the closure of the first gate - the left - materializes the work of about three months (the entry to the GAD began nine months ago), which had the work of divers, contractor personnel and EPM experts, who supported by specialized equipment and cranes recomposed and coupled the heavy structure to the servomotor.

Underwater work

To achieve the closure of the left gate, it was necessary to clear the "pocket" area where it lodged and remove the sheet that had the bottom of the tunnel, and then proceed with the closing of 50% of this tunnel.

In a high engineering task, a group of divers did the underwater tasks, consisting of the dredging and the removal of sediments, rocks and metallic material that prevented the correct closing of the two gates in the GAD.

The work of the divers was complex, due to the zero visibility, since neither the sunlight nor the artificial light could enter this point. To achieve progress, a 2D sonar was used, an electroacoustic device that emits acoustic waves and through the Doppler effect allows to visualize in real time the behavior on a computer screen. With this technological help, the diving supervisor advised and recommended underwater work. The diving applied was semi-autonomous with air supplied from the surface.

The water was drained with hydraulic and pneumatic dredges and divers drilled large rocks using special tools. Another challenge was to cut the metal sheets under water, with the safety conduits.

What follows

After the closing of the GAD left gate, the works focus on closing the right gate to complete the total closure.
At this time the assembly of the right gate, with a weight also of 300 tons, which broke into three pieces during the plugging and natural destacking of the auxiliary diversion tunnel (GAD) in the beginning of the contingency in the hydroelectric project Ituango
As it happened with the left hatch, specialized divers will clean the pocket of the right hatch so that in the coming weeks it will be closed and the closure of the GAD will be definitively achieved.

This advance will make it possible to build the 22 meter plug downstream of the dam chamber on the axis of the dam and thus advance in the reduction of the risks of the communities located downstream of the main works of the future power plant.

This EPM release was published using machine translation.