On Friday night, the rescue efforts at the Uttarakhand tunnel collapse site encountered a second interruption within a two-day span. In response to this development, the rescue team deployed geophysicists to assess the nature of the obstacle faced by the auger machine employed for drilling. The team utilized Ground Penetration Radar (GPR) to identify the materials causing the obstruction.
As per information from the National Disaster Management Authority (NDMA), as reported by ANI, it has been ascertained within Uttarkashi\’s Silkyara tunnel, where 41 workers are trapped, that there are no obstacles in the upcoming 5 meters.
During a press briefing in New Delhi, NDMA member Syed Ata Hasnain conveyed, “Using ground penetrating radar, it has been detected that there is no obstacle in the next 5 meters on our path. We continue to use this to detect obstacles, if any. There is hope that the movement of the auger is done and will be smooth until 5 meters, and again, this ground-penetrating radar will be used.”
Ground Penetrating Radar:
The Ground Penetrating Radar (GPR) utilizes electromagnetic waves for creating subsurface images, according to a ScienceDirect journal.
GPR employs radio waves to capture below-surface images in a minimally invasive manner, enabling the identification of underground utilities without ground disturbance.
It is a “non-intrusive and non-destructive technique” for subsurface surveys, proving valuable for exploring various materials and detecting structural changes and material differences.
GPR data is collected by moving antennas across the ground or walls, recording transmissions and receptions at different spots, which are then merged to form a \”radargram.\”
GPR equipment includes components like a waveform generator, a transducer with emitting and receiving antennas, a signal processor, and a data storage or display unit.
Its waveforms can identify empty spaces within concrete, and it has superior depth penetration compared to other non-destructive methods.
Update on Tunnel Rescue Operation:
The ongoing rescue operation at the Silkyara tunnel in Uttarkashi, where 41 workers have been trapped for over a week, faced another pause due to a technical issue encountered by the rescue team on Friday evening.
Officials reported a hindrance with the auger drilling machine shortly after it resumed drilling on Friday, following a day-long halt due to a previous technical problem. Although the initial issue was resolved earlier in the day, allowing the 25-tonne machine to restart, the operation had to be halted once more due to a second setback within two days.