Former Executive Director, NHPC Ltd.
Online published on 12 January, 2016.
During tunnel execution encountering of thrust zones, shear zones, fracture zones, fluvioglacial material, sandy, silty or clayey strata, overburden material is very common. This type of strata makes tunnelling extremely challenging. Over and above encountering of seepage water creates flowing ground conditions and makes worst tunnelling conditions for excavation of underground structures. Tunnelling becomes very difficult and slow.
By adopting new methods like Ground Freezing, Pre Grouting of Face with New Materials, Fibre Shotcreting with new materials and roof protection the weak strata can be strengthened inherently.
The Paper deals with various new methods and new materials for controlling the weak zones and successful tunnelling.
