SLBC tunnel clears shear zone hurdle
Telangana : The Srisailam Left Bank Canal (SLBC) tunnel excavation has made a key breakthrough with workers successfully crossing a dangerous shear zone.
A shear zone is a weak geological section where intense pressure and stress can cause rocks to shift and become loose. The same area had witnessed an accident in the past.
Bypass tunnel crosses vulnerable section
To avoid the dangerous zone, officials have been excavating a bypass tunnel alongside the original tunnel. The bypass also encountered a 10-15 metre stretch identified as a shear zone, but excavation through the section has now been completed successfully.
Officials expect tunnel excavation to progress faster from here and help accelerate completion of the project.
The bypass tunnel has been constructed alongside the tunnel where the earlier accident occurred, with the bypass on the left and the original tunnel on the right.
Excavation pace to increase in phases
Officials have set a target of excavating 350 metres every month after September and increasing the pace to 425 metres a month after January.
They are also expecting another challenging section ahead, but expressed confidence that it can be crossed safely.
The SLBC tunnel project has faced major geological challenges, including weak rock formations and shear zones. A roof collapse near Domalpenta on February 22, 2025, halted work and prompted plans to bypass the vulnerable section.
