Predicting the unpredictable in tunnelling

Tunneling for infrastructure projects is becoming more and more mechanised by use of tunnel boring machines (TBMs) and other methods. However, the drill and blast method is more flexible as it is easier to adapt to varying profile requirements as compared to a TBM, which gives a circular cross section, especially for railway tunnels, resulting in a lot of over excavation in relation to the actual cross section needed.Major tunnelling method used by L&T is the drill and blast method. “The goal of modern tunnelling technologies is to convert the unpredictable to predictable,” said Prabhukumar LT, Assistant General Manager of L&T ECC.On the challenges faced in tunnelling, he said “Many projects are coming up near the Himalayan mountains. The Himalayan range are young mountains with highly varying geology, coupled with diversified problems such as difficult terrain conditions, thrust zones, shear zones, folded rock sequence, in-situ stresses, rock cover, ingress of water, geothermal gradient, etc., which makes them highly unpredictable. Major challenges faced by us are the geology and predicting things ahead. Due to unpredictable geology, safety is compromised during project work, which leads to extended project completion and cost over run.”To read full article: Click here