Pick the right alignment to avoid construction of big bridges and roads, says RVNL CMD | Business News

What’s the significance of the Rishikesh-Karnaprayag line?

The Rishikesh-Karnaprayag Railway line is vital primarily for 2 causes. First, it’s rail connectivity to the individuals within the distant areas of the hills. Out of 125 km of the mission, a complete of 105 km goes by way of the tunnels after which bridges. So, just about aside from yards, it’s a fully underground prepare. It would present protected journey in all climate as roads constructed alongside the hills are all the time weak to landslides.

Secondly, it’s a motion in the direction of the China border. That is declared a strategically vital mission. Thus far, it’s as much as Karnaprayag, nevertheless it has been deliberate to take it past. All it will assist to maneuver the heavy Military equipment to the border in a camouflage situation as a result of nearly all of the motion will likely be executed below the tunnel.

The road will likely be prolonged to Joshimath, Gangotri, Yamunotri for Char Dham. We’ve already submitted the Ultimate Location Survey and detailed value to the Railway Board. The extension mission is but to be sanctioned. The Military needs to increase it to Mana, which is positioned at a really excessive degree, nearly 3,500 m above sea degree. Will probably be taken so far as we are able to take this line.

Why did you employ the Tunnel Boring Machine (TBM) in T-8?

We acquired this mission in 2012 and after an in depth survey, we submitted the estimates to the federal government in 2016. From 2016 to 2019, we did an in depth investigation, accomplished land acquisition and forest clearance. We began engaged on the mission in 2020.

T-8 goes to be the longest tunnel in India. Beside these two openings, there was not any chance to have some other opening on this stretch. If we might have excavated this tunnel by way of the standard technique, it could have taken 9 years to finish it. So, due to uniform geological circumstances, we determined that we’ll use the Tunnel Boring Machine (TBM). Often, persons are not assured in utilizing TBM within the Himalayas, and rightly so, as a result of there are a lot of circumstances of failure. Along with the geology, the motion of tectonic plates additionally makes tunneling troublesome. The geology of the Alps mountain vary is much like ours, however the motion of tectonic plates make it tougher.

The geology of the rock within the tunnel might be understood as the common MPa (a unit of strain generally used to measure the compressive energy of rocks) of the rock is round 35. Whereas the granite has greater than 200 MPa. So the mountain could be very fragile and as we transfer forward excavating, there may be all the time a threat of compacting or shrinking of the opening, which may additionally result in a collapse.

How did you overcome these challenges?

Look, given the geology of the world, it was apparent that we’ll face a lot of challenges. However we anticipated all these items prematurely and deliberate accordingly. The vital factor about tunneling is what you’ll be able to predict. To make sure protected and environment friendly excavation, one has to foretell all of the potential issues that will happen in the course of the work. When you do that, you can be totally ready.

So, we did an in depth investigation with Airborne Electromagnetic testing. Beneath this system, there’s a huge body which is carried by the helicopter over the alignment. The machine bombards the electromagnetic radiation, which strikes on the alignment. Utilizing this know-how, we acquired to know concerning the mountain strata.

Second, the equipment used within the tunnel is the newest state of artwork equipment on the planet like jumbo dills, loaders, shotcrete machine, multi-service autos, and many others.

As an example, in drill and blast, first we drill a gap after which match it with explosives for the blast. Now the alignment of the outlet is essential. Should you drill the outlet appropriately, it’s going to blast precisely as a lot as you designed. Should you drill it crookedly, it’s going to overbreak the rock. Utilizing these newest machines, we’ve got by no means had any drawback with overbreaking.

Together with this, we streamline the tendering system. We took the geological threat on our head in order that the contractor doesn’t really feel overburdened with the considerations of mishappening. We owned up the investigation that if something goes improper, RVNL will compensate the contractors. It was one of many largest components which gave them confidence.

How was the alignment of the road determined?

Tunneling doesn’t imply to name a young and ask the contractor to excavate the mountain. We must always spend on “Sharpening the axe”, like different developed international locations do. We did round six years of investigation and if we had not executed this, we might not have been capable of obtain all this. In case you are making an alignment, which avoids the harmful pitfalls, half of labor is finished.

From which international locations have been the machines procured and the way have been they transported to the location?

The equipment used within the tunnel was purchased from two corporations, Swedish firm Epiroc, a Finnish firm Sandvik. We purchased nearly 40 totally computerized machines for the tunnel. TBM was purchased from the German firm Herrenknecht. The vital factor is that the machine was manufactured in Germany, dropped at Mundra port after dismantling it after which dropped at the location. We confronted challenges in transportation after Rishikesh because it lies within the hilly space.

There’s a small bridge spanning nearly 100 m on the Ganga. We didn’t know the load carrying capability. As a result of, with out understanding the capability, it was not potential to move such heavy equipment. So we did a load take a look at.

The heaviest a part of the machine was 168 tonnes. That was an enormous problem. We needed to hold it in a single single piece. We may have dismantled it and transported it half by half, however we couldn’t have achieved ending whereas assembling on the website as in comparison with the manufacturing unit ending.

Another excuse is that essentially the most crucial a part of the TBM, which is named major drive, had the probabilities of shields being broken. You can’t drive the TBM if the defend is broken and the substitute of those components contained in the tunnel was nearly unattainable. So we didn’t take any probabilities on this.

Together with this, there have been probabilities of mud accumulation and ingression on the website throughout assembling the TBM, which had a really dangerous impression on its working and dirt particles may minimize the defend. So it was determined to move it in a single half.

It’s a Rs 250 crore machine. Its dimension was additionally giant, nearly 6.8 m. So, within the slim space, we needed to carry it and stand it vertically utilizing the crane. After crossing the slim street, we once more made it horizontal. It took 2.5 months for the whole assembling of the TBM.

What’s the purpose for utilizing two tunneling strategies?

From ordering a TBM to the commissioning, it takes nearly 16 months. So on this tunnel, as it’s 14.57 km lengthy, we didn’t await the beginning of the TBM and started excavation by way of New Austrian Tunnelling Methodology (NATM) from the opposite aspect. The precise TBM excavation began in March 2023. Out of the 14.57 km, 10.47 was excavated by way of by TBM and 4.11 km by NATM. It took 760 days to excavate 10,470 m by TBM. So the common progress was 415 m per thirty days.

It’s the world’s second quickest excavation within the class of 9-10 m tunneling. The quickest is 423 m per thirty days in Spain’s cabrera tunnel. However that they had good geology of limestone. Our geology is of phyllite rocks. Stronger the mountain, the simpler it’s to tunnel in it.

Kashmir Rail Hyperlink can be an analogous mission. Had been there any learnings drawn from it for the Rishikesh-Karnaprayag Line?

Sure, a very powerful studying was the alignment to keep away from any further expenditure. Within the Kashmir rail line, accessibility was a serious problem. The alignment was deep into the world which was distant, the place there was no connectivity by the street. So we needed to construct a street for transportation of equipment. We constructed strategy roads of 215 km.

On this alignment, we took care of these items that permit’s not make huge roads and let’s have tunnel portals close to the highways or the place there may be an accessibility. So we made solely 11-12 km street on this mission. Thus the extra work might be prevented.

There are huge bridges like Chenab and Anji Khad within the Srinagar line. On this, we took an alignment in such a matter that we wouldn’t have to construct huge bridges. On this mission, the bridges are a most of fifty m excessive. It saved us some huge cash, time and sources.

What’s the completion goal for Rishikesh-Karnaprayag line?

Our goal is to start out the operation of the prepare by December 2026. The full tunneling on the road is 213 km, which incorporates major tunnel, escape tunnel, out of this, 195 km is full. All this has been executed in simply three years and 9 months. Our goal is to finish the excavation by the top of this 12 months.

What’s the subsequent main mission of RVNL?

Our subsequent main mission is 63-km lengthy Bhanupli (Punjab) to Bilaspur (Himachal Pradesh) line, which can additional go as much as Leh, Ladakh.