TBM Now Mining Faster Than Planned

This just in --

The TBM under Second Avenue mined a total of 92.74 feet (in single day) yesterday, which I believe is the maximum achieved production on this project to date.

This single-day production level is greater than the 50 feet/day estimate that MTA Capital Construction is using for planning purposes, and I understand that it's even further than the 65 feet/day that the contractors (S3 Tunnel Constructors) said would be possible when they bid the job.

The machine has now mined a total of 1,760 feet of TBM Run No. 1 (i.e. the west tunnel) as of yesterday - which by my calculations would put it at about 85th Street.

Next stop (for this TBM), is 65th Street.

A Footnote:
One naturally might wonder how it is that they know the machine moved exactly 92.74 feet on Wednesday.

The answer... They measure the distance by shooting an invisible infrared laser, from something called a Total Station, at a pair of retroreflector prisms that are mounted on the machine's head. The Total Station calculates the distance using an optical technique known as phase measurement. The data from the Total Station is then fed to a computer inside the cab of the TBM, so the operator knows exactly where he is at all times.

I'm told that this method of measuring distance is accurate to about 1/1000 of a foot (which is 0.012 inches).

Down in the Tunnel

And at long last, we now have a few images of the work taking place inside TBM Tunnel No. 1 (the west tunnel) under Second Avenue.

The quoted text under each image is the caption that was provided to me by the MTA.



Courtesy of the MTA
8/2010
Inside TBM Tunnel No. 1
"General view along the TBM catwalk of the bridge conveyor and spoils [muck] being removed from the heading."



Courtesy of the MTA
8/2010
Inside TBM Tunnel No. 1 - looking south
"General view of extended vent line and locomotive pulling muck cars from the starter tunnel."



Courtesy of the MTA
8/2010
Inside TBM Tunnel No. 1 - looking north
"General View of full muck cars being hauled out of the tunnel."



Courtesy of the MTA
8/2010
Inside TBM Tunnel No. 1 - looking south
"A view of the steel rib initial support installation."


::


And here are a few images of the work taking place at street level on Second Avenue.



8/21/10
69th Street - looking N

The access shaft shown in this image is now complete and the the contractor, S3 Tunnel Constructors, has now removed all of their equipment from the work area. Its nice to see how neat the contractor has left this work site.

This shaft, and its twin up near 72nd Street, is now ready for a new contractor to start mining the cavern for the new 72nd Street station in the not to distant future.



8/21/10
btw. 83rd & 84th streets - looking N

This looks like a new gas main that is undergoing a pressure test. This is done by pressurizing the new section of pipe with a non-flammable a gas and then checking to see that the pressure in the pipe remains constant for a fixed period of time.

Note the orange tanks in the image are marked with HAZMAT Class 2 "non-flammable gas" placard. One could assume that these tanks contain the gas that is being used for the pressure test.



8/21/10
91st Street - looking S

Workers here are preparing the area between 90th and 92nd Street, on the east side of Second Avenue, that will be subject a "ground freezing" process.

The ground in this area must be frozen before the TBM starts mining tunnel No. 2 (the east tunnel) because this area contained fractured rock and soft ground - materials that cannot be mined by the main beam TBM that is being used on this job.

Before the ground can be frozen the surface must first be prepared and a network of freeze pipes must be installed. Before the TBM starts its run for the east tunnel the ground in this area will be frozen solid.

After the TBM passes through this area an interim liner will be installed through the frozen zone to seal the ground and the groundwater from entering the tunnel as the ground thaws out. This interim liner will be incorporated in the final cast-in-place liner after this tunnel has been excavated.



8/21/10
91st Street - looking N

Another view of the surface preparation work in the zone where the ground freeze will take place.



8/21/10
In front of 1867 Second Avenue (btw. 96th & 97th streets) - looking S

At this location the contractor is using a technique known as compaction grouting to improve the soil conditions under the buildings at 1867, 1869, and 1871 Second Avenue.

The image above shows one of the drills that is being used to install the grout pipe. The temporary pedestrian access way to the front door of 1867 Second Avenue can be seen on the right.



8/21/10
In front of 1871 Second Avenue - looking S

A close-up view of the 2nd drill unit, which is located in front of the McDonald's restaurant.


::


The MTA recently announced (on their web site) that the following two contracts are to be advertised in the near future:

Contract C-26008
Mine 86th Street Station Cavern
Second Avenue Subway
This project is to mine the 86th Street Station cavern as well as shafts and adits for the entrances, elevator, electrical, ancillaries, cross passages, underpinning of existing structures and cut and cover excavation.

Contract C-26009
Construct Track, Signal, Power & Communications Systems
Second Avenue Subway
This project is to construct track, signal, traction power, and communication systems for the Second Avenue Subway which includes the 96th, 86th, 72nd and Lexington/63rd Street Stations.


::::


Here's a listing of the recent additions
to the right-hand column of The Launch Box:

"Bring on the MTA Machines"
By Kelli Gail
Our Town - 8/18/10

Committee Report (7 pages)
Hearing Testimony (39 pages)
Hearing Transcript (141 pages)
"The 2nd Avenue Subway and the East Side –
Is there light at the end of the tunnel"
Oversight Meeting
Joint Committees on Small Business and Transportation
New York City Council - June 14, 2010


Under Businesses that have Closed:


8/21/10
1830 Second Avenue (btw. 94th and 95th)
Chinese Mirch - a take away restaurant
Closed at this location in August 2010



8/21/10
1817 Second Avenue (btw. 94th and 95th)
Re-opened as Konomi Sushi
in early August 2010


Under Notices & Posters:


8/21/10

Heads Up!

What follows is a story about an incident that occurred on Friday, August 6th, near the corner of East 93rd and Second Avenue.  Because the events in the story happened to me -- of all people! -- I have written about this in the first-person narrative.

I would have posted the story earlier but until recently I was away on vacation in Quebec.

::

On Friday morning, August 6th, I left my apartment at about 7:30 a.m. to walk to the local cleaners on East 93rd Street. 

My walk took me past the vertical elevator (shown below) that was in operation at the time. [This machine is used to transport the spoils, also known as muck, from the TBM mining operation that is underway below Second Avenue.]



6/18/10


As I walked past the machine, I spotted a small 2 inch piece of gray rock on the sidewalk in front of the Subway sandwich shop at 1776 Second Avenue.

I picked up the rock and examined it -- and then decided that it surely must have come from the subway mining operation. I put the piece of rock in my bag and walked on.

Before continuing on to work, I decided to return to the same location to look for any additional rock samples.

I was standing on the fence line with my back to the machine when, all of a sudden, I heard a loud "thump." I was startled by the sound and, when I looked down at the ground, I noticed a larger and heavier piece of rock (shown below) that had just landed right next to me on the sidewalk!



8/6/10
Length - 3 1/2 inches  /  Weight - 13 ounces


This second and larger piece of rock apparently had become caught in the machinery, and then was ejected from the high speed conveyor belt.  The rock had flown through the air and then bounced off the top of a green storage container at this location. It then landed on the sidewalk beside me.

As I picked up this new piece of rock, I realized just how lucky I was that the rock had not hit me in the head, instead landing "safely" just beside me on the sidewalk.

I put this new piece of rock in my bag and moved away from the fence line.

As I continued on my way to work, I looked down the lane where the trucks were being loaded with muck.  I made a mental note that the muck that was now being loaded into the trucks included larger chunks of rock (like the one that almost hit me).  Most of the muck being taken out of the launch box before this day was of a finer, almost powdery, consistency.

As soon as I got to my office, I called Claudia Wilson, the MTA's Community Liaison for the project, to report what had just happened.  She said that she would contact the construction manager right away.

By the time I returned home that evening, a large piece of blue material (shown in the images below) had been draped around the top of the vertical elevator structure.

One could assume that this blue material was set up to keep stray rocks from being ejected in the direction of the sidewalk.



8/7/10



8/11/10
An aerial view

If you look closely at the brownish-orange storage container, in the images above and below, you can see that there are at least a dozen rocks of significant size on the roof of the container -- which would suggest to me that the vertical elevator had been a ejecting rocks for some time now.



8/11/10


In the last several days, people who live above this area have told me that all of the rocks on the top of this container have since been removed -- I assume by the contractor.

One could logically wonder why no sidewalk sheds have been set up near this machine to protect pedestrians on the sidewalk. However, maybe it is simply because the NYC building code does not require them in this situation.  At the very least, the fence line could be moved back further away from the machine by a few more feet.

I, for one, will now take a wider path around this machine in the future.


::


In other news, the MTA reported to me earlier this week a few details about the location of the TBM under Second Avenue.

As of last Friday, August 13th, the TBM has mined a distance of 1,264.7 feet - which by my estimate (using the Google Maps distance measurement tool) would put it 50 feet south of East 87th Street.

I've also been told that the TBM mined a total of 87 feet on August 12th, which is the maximum achieved production to date.


:::::


Here's a listing of the recent additions
to the right-hand column of The Launch Box:

Second Ave. Subway merch: A tee for the T
2nd Ave. Sagas - 8/3/10

Synopsis of Determination and Finding Pursuant to Article 2 of the New York Eminent Domain Procedure Law - Contracts 3, 4 and 5 of Phase 1 of the Second Avenue Subway
via the New York Post
Metropolitan Transportation Authority - 7/20/10
Oddly, as of today I have been unable to find a copy of this Official Notice on the MTA's web site.

A TBM on the Move

Work underground is progressing and the TBM, as I type this posting, is boring its way south, deep under Second Avenue.

From the MTA's perspective the TBM officially started excavating Tunnel No. 1 (the west tunnel) on Tuesday, June 8th - about 7 weeks ago. Since then the cutterhead of the TBM has carved out 657 linear feet of tunnel, as of last Thursday, July 29th.

The MTA has said that the first 700 feet or so of the TBM's operation would be the test period - when they knew that it would be a challenge to get the various systems, on the newly assembled machine, working properly together. Considering the problems over the past 2 months, some might say that this was a bit of an understatement.

One senior official inside the MTA has even gone so far as to say that during the early going they have been "plagued with technical problems" - electrical problems, problems with the electronics, problems getting the grippers to apply the proper amount of force, and problems with the drive shaft on the TBM, that ultimately had to be replaced - as well as the numerous problems with the high-speed conveyor systems (with being parts flown in from Switzerland.)

And then there was the poor rock that they encountered for the first 200 feet of so of TBM mining (between 91st and 92nd streets.)

The rock in this area under Second Avenue is heavily fractured and it contains numerous faults and seams. The TBM that is being used on this project has a tough time working its way through fractured rock because the grippers (the arms that push the TBM forward into the rock face) can't properly grip the rock without crushing its structure - and if the grippers crush the structure of the rock behind the cutterhead you don't have a tunnel that can support itself.

The contractors have also had to install steel rings to support the tunnel in this section. I'm told that the MTA was also concerned about the possibility that the grippers might damage the integrity of rock between Tunnel No. 1 and what will become Tunnel No. 2 in this area, by applying too much force on the rock, so it was very slow going for the TBM for the first few weeks.

Then there was the runaway TBM probe drill that surfaced on Second Avenue back on the morning of July 8th.  This incident cost a considerable amount of time due to the ensuing investigation.

But now the MTA believes that the contractor has worked out the last of the kinks with the systems on the TBM and the machine has moved passed the area of poor rock in the low 90s.

On July 24th, when the contractor worked on a Saturday to catch up a bit, they had the first good production day of mining with the TBM. (I'm not exactly sure what this means in terms or production, but one might guess that on this day the TBM mined about 50 feet of the new tunnel.)

A side note about the expected production rate of the TBM -- the contractor has the machine scheduled to operate 24 x 5 at the moment (i.e. 24 hours a day, 5 days a week [M-F]).  They [the contractor] have said that the TBM should be able to mine at a rate of about 65 feet per day, but for planning purposes the MTA has used a rate of just 50 feet a day, to be conservative.  Needless to say, we're still waiting to hear (officially) about a 50-foot or better production day.

But with all of that said the  MTA remains confident at this point that the TBM will finish its 7,200 foot run to 65th Street by early January 2011.  At that time the TBM will back up to the launch box and start mining Tunnel No. 2 (the west tunnel).

In other news --

• MTA sponsored repairs are underway in the buildings between 95th and 96th streets - and I'm told that the residents who were temporary relocated at 1723 Second Avenue were able to move back into their apartments on Saturday, July 24th. (These are some of the buildings that the MTA and the DOB had determined needed to be worked on to repair a number of structural conditions.)

• A total of 88 buildings, near where the 72nd Street station will be built, have now been surveyed by the MTA's contractor to check for structural issues, and a total of about 20 of these buildings were characterized as "problematic." The MTA is now working with Department of Buildings to determine how much repair work needs to actually be done by the MTA. The survey also showed that 4 of the buildings required urgent attention due to structural deficiencies that the survey identified. The MTA is "cautiously optimistic" that they will not have to temporary relocate any residents in this area while any necessary building repairs are made.

• The MTA is now in the process of qualifying the 2nd lowest bidder for the 72nd Street Station Cavern Mining Lining and Heavy Civil contract, which is known as Contract C-26007. The lowest bidder, OHL/Tully Cavern JV, who had bid $319,229,925 has "declared a mistake" [with their bid] and they apparently are no longer being considered for this contract. OHL/Tully Cavern JV had bid $127 million (30% less) less that the 2nd lowest bidder SSK Constructors JV, which I understand is a joint venture between Schiavone Construction and J.F. Shea Construction.

::

Now on to a few new images.


7/31/10
Just N of 72nd Street - looking NW

What you see here is top of the [now complete] access shaft at 72nd Street. The top of the shaft,as shown in this image, has been covered over with concrete decking.

This shaft will be used later in the project during the mining and construction of the 72nd Street station. When the project is complete the shaft will be filled in and covered over with a new road surface.


7/31/10
72nd Street - looking N

Another view of the completed shaft at 72nd Street.

Work on the 69th Street shaft is still on-going, but I've been told that the blasting work at this location has now been completed.

Note the colored sign on the right side of the image. It say that "work on this project is scheduled to be completed by [the] summer of 2011."  This statement is a bit misleading (for the general public) in my view since work at this location is actually scheduled to continue until late 2013 while they mine and construct the 72nd Street station.

Oddly the sign also make reference to the 96th Street station.  People on the street who view this sign might ask themselves, "what part of the 96th Street station is being constructed here at 72nd Street?"


7/31/10

This is the front end of a 30" ball valve that is being prepared for installation. Most likely it will be used to regulate a new gas main that runs under Second Avenue.


7/31/10

Another view of the same valve.

Short sections 30-inch pipe, each about 4 feet long, have recently been welded to the valve on the left and the right.  (the valve itself is the black round section in the middle, with the actuator on top.)



7/31/10

This is a closer view of weld between the pipe and the ball valve.



7/31/10

And a much closer view of the weld.  To be sure, this weld is the work of a high skilled craftsman.




7/31/10
83rd Street - looking W

An extensive amount of utility relocation is on-going in this area as one can clearly see in this image.


7/31/10

Two sections of cast iron pipe, an old fire hydrant and a pigeon are shown in this image.


7/31/10
Just south of 91st Street - looking NW

Workers have recently removed the road surface from this location in preparation for the "ground freezing" procedure that will be setup at this location before the TBM starts to mine Tunnel No. 2 (the east tunnel) in early 2011.

The ground on the east side of Second Avenue between 90th and 92nd streets (approximately) must be "frozen" because the structure of the rock at this location is too weak for the TBM to operate properly.


7/31/10
btw. 93rd and 94th Streets - looking W

This large container caught my eye when I walked by it on Saturday.  According to the label on the side, the blue liquid is Midfloc 1315L, an industrial chemical compound called Anionic Flocculant.  This product is used to remove suspended particles in waste water. (if you click on the chemical name there is a brief video that shows how this product works.)


7/31/10

This is a view of the undercarriage of the Liebherr HS 885 crawler crane that is currently located between 94th and 95th streets.


7/31/10

And this is a closeup view of the mechanism that is used to rotate the crane,



7/31/10
95th Street - looking N

This is a section of newly completed sidewalk on the east side of Second Avenue.  It may not look very exciting, but for the past few months residents in this block have had to use a temporary protected walkway that had been setup in the middle of Second Avenue.


::

A footnote:
A few people have asked me why I don't have any pictures of the work that is taking place down in the tunnels.  The simple answer is that don't have access to the work site, above or below ground.

With that said, if any of the workers or contractors wish to share any of their images that they have taken of the work taking place underground please feel free to send them to me via e-mail.  Or if they're posted somewhere on-line please just tell me where to find them (e.g. on the Flickr web site). 

You can find my e-mail address in the right-hand column of this blog.

Ben


: : : : :


Here's a listing of the recent additions
to the right-hand column of The Launch Box:

"Feds See 'Grim' Delays, Overruns on Second Ave. Subway, East Side Access"
By Eliot Brown
The New York Observer - 7/9/10

"New York Truck Companies Investigated for Fraud"
By William K. Rashbaum
The New York Times - 7/9/10

"Equipment failure delays 2nd Ave. subway AGAIN!"
By Pete Donohue
Daily News - 7/27/10

"Picture This, and Risk Arrest"
By Jim Dwyer
The New York Times - 7/27/10
An interesting article about what happened to a guy who decided to take a few pictures of Amtrak trains at New York Penn Station.  (This isn't really related to the 2nd Avenue subway - but it is interesting for photographers like myself.)

"Business Slides on Second Avenue As Subway Construction Drags On"
By Joseph De Avila
The Wall Street Journal - 7/31/10


Delays, overruns again plaguing Second Ave. Subway
2nd. Ave. Sagas - 7/9/10

Inside the subway station of the future
2nd. Ave. Sagas - 7/15/10

Underneath 2nd Ave., a TBM struggles to move forward
2nd. Ave. Sagas - 7/28/10


The Blog Below
An interesting blog about subterranean spaces and tunnels.  Unfortunately the author stopped posting in late 2008.

The Underground Construction Association of SME
The home page of the Underground Construction Association of the Society of Mining, Metallurgy and Exploration.


Blog
the Wikipedia entry for the word "blog".


Last Reported Location of the TBM
~20 feet north of 89th Street
as of Thursday, July 29th

TBM Run No. 1 (west tunnel)
92nd Street to 65th Street
7,200 linear feet
40 foot starter tunnel
657 feet mined w/TBM to date
6,503 feet to run