Takeaways from Recent International Symposium on Tunnelling at IIT Delhi

 S C Mittal

 Chairman and Managing Director, DMR                                                                                      

                                                                                                                                                                                                          6^th Dec 2023

IIT  Delhi symposium sponsored by SJVN on Tunnelling was successfully held on 2nd and 3rd Dec 2023 at IIT campus. DMR team was invited as participants in the symposium. The recent Silkyara Tunnel Rescue operation brought out the importance of Safe and Reliable Tunnelling Methods. In this Background, Importance of this Symposium to deliberate on challenges and solutions to Tunnelling was realised by the participants and speakers.     

It is unusual that symposium was held on weekend instead of week days. Active participation of several Eminent international Experts from Across Globe was another interesting highlight.  IIT organising team was smart  to organise a professionally engaging seminar on the topic. The symposium was broadcast Live on YouTube.

My Key Takeaways from the Symposium are:

1. The symposium was made interesting and lively with participation of Dr. Nick Barton, Dr. Robert Galler, Dr. Bineshian Hoss and Dr. Arnold Dix and other prominent International and National Experts on the subject.
2. Several Methods Exist for Rock Mass classification and designs of tunnels such as RMR system, Q system and I-System.
3. I-system by Dr. Bineshian Hoss is the latest and most versatile methods of design applicable for both Rock and Soils : This method is yet to gain popularity.
4. NATM and NMT are two different approaches to Design and construction which are presently adopted.
5. A lot of tunnelling is happening in India which require large number of trained resources to be available at Remote Project Sites.
6. Tunnelling in Deccan trap is different from Tunnelling in Himalayas.
7. There is need to do better in tunnelling in India for better safety in tunnels. Ecosystem for tunnelling has to be improved.
8. There are several aspects of tunnelling which need to be thought together – Design, Contracting, Construction, Monitoring and Evaluation.
9. Tunnel Monitoring is the most important input towards Safe Tunnelling. Monitoring generally remains neglected part of Tunnel Construction.
10. Drill and Blast remains the most preferred method of tunnelling in Rocks in India.
11. Tunnelling in soft ground is different from tunnelling in Rock.
12. TBM tunnelling is gaining its application more and more. There are issues in the design and construction of TBM tunnels.
13. Silkyara like episodes are avoidable and should be avoided. Monitoring and follow up action on monitoring are key to avoiding future events.
14. There is a need to develop sufficient expertise in Tunnel monitoring in India
15. Geological model of Tunnel during construction is found to be significantly varied compared to DPR/ tender in several cases.
16. Technology/ Methodology/ BOQ to deal with difficult ground conditions should be separately provided in Tender and be available in construction.
17. Pre- Grouting is an important means of intervention to avoid collapses at Face and also to treat collapsed face.
18. Quick Decision Making during construction and adjustment of construction costs are very much required for safe tunnelling and should invite attention of top Managements, Regulators , Policy Makers and other involved agencies.