Mitigate the Instability in Conventional Method of Tunneling Khali R.K.1, Bahuguna Naveen K2 1Asstt. Vice President-Hydro, GVK Project & Technical Services Ltd, Gurgaon, Haryana 2Sr. Manager-Hydro, GVK Project & Technical Services Ltd, Gurgaon, Haryana Online published on 25 April, 2013. Abstract Drilling and blasting is the predominant conventional method of excavation in tunnels, timely completion of tunnels in hydro Electric projects has a long term impact on the project economics, designing the optimum pull based on rock mass conditions is the main task for a tunneling engineer. A poor method of charging the holes and using the wrong blast pattern during the tunnel excavation may often lead to serious problem in terms of roof stability and cost of extra support. The ideal blast results is a minimum to the damage of rocks that remains and minimum of overbreak, less rock damage means greater stability and less ground support required. The stability of underground structure is much dependent upon the integrity of rock immediately surrounding the excavation. Therefore the poorly blasted rock can give rise to serious instability problem in the tunneling. Faster tunneling rates within minimum over break is possible with optimized longer pull per blast without affecting the economics of the project This paper discuss the different methods and practice of minimize the underground instability due to blasting and also discuss how to improve the advance rate in conventional method of tunneling. Top |