India's first underwater tunnel in West Bengal to be 45-sec experience for metro passengers
Howrah/Kolkata (PTI): India's first underwater tunnel, being built under the Hooghly River in West Bengal at a cost of around Rs 120 crore as part of the East West Metro Corridor, will be a blink-and-you-miss-it experience for passengers as trains will cross the 520-metre stretch in just 45 seconds.
The tunnel -- the Indian version of Eurostar's London-Paris corridor -- is 13 metre below the riverbed and 33 metre below ground level.
The 520-metre tunnel is part of the East West Metro Corridor of Kolkata -- from the IT hub of Salt Lake Sector V in the east to Howrah Maidan in the west across the river.
The tunnel's construction is complete and is likely to be commissioned in December 2023 after the completion of a 2.5-km stretch between Esplanade and Sealdah on the corridor.
"The tunnel is essential for the East West Corridor and it was key. The under-the-river-alignment was the only alignment possible with residential areas and other technical issues involved," said Kolkata Metro Rail Corporation General Manager (Civil) Sailesh Kumar.
"This metro route between Howrah and Sealdah cuts down the commute time to 40 minutes as against 1.5 hours by road. It will also ease congestion at both ends," he said.
It will take 45 seconds to cross the tunnel, he said.
The East West Corridor of the metro rail has been marred by delays and resultant cost escalations. It was approved in 2009 at a cost of Rs 4,875 crore and a completion date of August 2015. According to officials, the cost has now increased to Rs 8,475 crore out of which Rs 8,383 crore has already been spent.
The tunnel will have an internal diameter of 5.55 metre and an external diameter of 6.1 metre. The spacing between the up and down tunnels will be 16.1 metre centre-to-centre.
The inner walls of the tunnel are being made with high quality M50 grade, reinforced concrete segments with a thickness of 275mm each. Six of these segments will complete a circular lining of the tunnel's diameter. The segments are being pre-cast in specialised moulds imported from Korea.
Several protective measures have been taken to prevent water inflow and leakages in the tunnel. Concrete mixes composed of fly ash and micro silica have been used for the segments to minimise water permeability.
The segments are being sealed using a complex grouting process that will fill the space between the segments and the shield of the tunnel boring machine (TBM).
A two-component grout mix, including a slurry made of water, cement and bentonite and sodium silicate, is being used to fill the gaps. The liner segments are fitted with German-made neoprene and hydrophilic auxiliary gaskets, which expand when in contact with water to prevent inflow through segmental joints.
Two German-made tunnel boring machines (TBMs), named Prerna and Rachna, were deployed for the process.
Emergency evacuation shafts up to 760 metre in length are being provided inside the tunnel in accordance with the National Fire Protection Association (NFPA) guidelines. The evacuation shafts are being provided in Howrah Station in the west and Strand Road in the east for passenger safety.
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I forgot that I can use saliva, but will use it from now on: RCB's Bhuvneshwar Kumar
Bengaluru, Apr 17 (PTI): Fast bowlers often have elephantine memory but Royal Challengers Bengaluru’s Bhuvneshwar Kumar rather sheepishly conceded that he has forgotten to use saliva to shine the ball despite the redrafted rules, and promised to make amends in the IPL match against Punjab Kings here on Friday.
In the run-up to this season’s IPL, the BCCI had lifted the ban on using saliva as a ball polishing agent after several captains favoured the move.
The saliva ban was enforced during the COVID-19 pandemic days as a precautionary measure.
Now, several skippers and quick bowlers have felt that it will revive the forgotten art of reverse swing, but Bhuvneshwar offered a different perspective.
“I forgot that I can use saliva. Yesterday when the (team) staff told me, I didn't know that I have to use it,” a sheepish Bhuvneshwar said on the eve of the match against Punjab Kings.
But now, there is a late realisation and he is open to experimentation.
“I am not sure if it will help or not, but now that I remember, definitely in tomorrow's match (vs PBKS) I will put some saliva and see if it helps or not," he said with a chuckle.
However, some of his contemporaries have eagerly latched on to the opportunity to purchase some reverse swing to keep the batters guessing.
Mitchell Starc of Delhi Capitals found a hint of reverse swing against Rajasthan Royals on Wednesday while homing in on the stumps with a series of yorkers in the 20th over and later in the Super Over.
Starc’s remarkable accuracy and the touch of reverse swing played a big role in DC eking out a Super Over win at the Arun Jaitely Stadium in the national capital.
“Reverse swing had completely gone away from cricket, whether it was red ball or white ball. Suddenly, if someone can execute 11 yorkers in 12 balls at a 145 (kmph) pace, then you have to give Starc the credit,” said RR’s Nitish Rana, who fell leg before to the Australian fast bowler.
Delhi’s skipper Axar Patel also offered some insight.
“Getting reverse swing is one thing, but executing it is very important. It was reversing, but at that time, under pressure, he (Starc) was executing it,” Patel said.
“I was just reminding him to be clear about the plans we made in the bowlers meeting. I was getting the same response: ‘Don’t worry, skip. I’ll do it',” he added.
rhaps, it’s time for Bhuvneshwar to do it as well.
